Bug: OAuth 2.0 State Parameter fails with Pipe Delimiters (RFC 6749 Non-Compliance)

Bug: OAuth 2.0 State Parameter fails with Pipe Delimiters (RFC 6749 Non-Compliance)

I've discovered a bug in how Zoho's API Console handles the OAuth 2.0 authorization flow when the state parameter contains pipe characters (|), and I'm hoping the Zoho team can address this in a future update.
The Issue
Zoho's OAuth 2.0 implementation for server-based client applications uses the standard authorization endpoint: 
https://accounts.zoho.com/oauth/v2/auth?response_type=code
    &client_id=<client_id>
    &scope=<scope>
    &redirect_uri=<redirect_uri>
    &access_type=offline
    &state=<state_value>
While Zoho's documentation does not explicitly list the state parameter, it is a standard part of the OAuth 2.0 specification (RFC 6749 Section 4.1.1) and is widely used for CSRF protection and maintaining application state through the authorization flow.
However, when the state parameter contains pipe characters (|), Zoho's authorization server fails to process the request correctly, preventing users from authorizing the connection. This occurs whether the pipe characters are URL-encoded (%7C) or left unencoded.
The Problem
The pipe character is a standard delimiter in multi-part state values, particularly when passing a combination of a CSRF token and a return URL. This behavior—failing on both encoded and unencoded pipe characters—is often indicative of overly restrictive input validation or a "leaky" WAF/Proxy layer that decodes parameters before the application logic can handle them.
State Value As Sent in URL Result
abc123xyz state=abc123xyz ✓ Works correctly
session_12345 state=session_12345 ✓ Works correctly
user|action|timestamp state=user|action|timestamp
(unencoded pipes)		 ✗ Authorization fails
user|action|timestamp state=user%7Caction%7Ctimestamp
(URL-encoded pipes)		 ✗ Authorization fails
user:action:timestamp state=user%3Aaction%3Atimestamp ? Not tested
Note: Pipe characters cause failures whether URL-encoded or not. Other special characters/delimiters have not been tested and may or may not exhibit similar issues.
RFC 6749 Compliance Issue
Section 4.1.1 - Authorization Request:
"state: RECOMMENDED. An opaque value used by the client to maintain state between the request and callback."
Section 4.1.2 - Authorization Response:
"state: REQUIRED if the 'state' parameter was present in the client authorization request. The exact value received from the client."
The RFC explicitly defines the state parameter as an opaque value. This means:
  • The Authorization Server should not be looking "inside" or parsing the string at all
  • The state value must pass through the authorization process unchanged
  • Any URL-encoded characters should be handled transparently
  • The exact value received must be returned to the client in the redirect
Key Point: By definition, an "opaque" parameter means the authorization server must treat it as a data blob—accepting it, storing it, and returning it without any interpretation or transformation.
Current Behavior vs Expected Behavior
Current Behavior Expected Behavior (Per RFC 6749)
1. Client sends: state=user|action|123
(or state=user%7Caction%7C123)
2. Zoho fails to parse the state parameter
3. Authorization server returns HTTP 400 Bad Request
4. User cannot authorize the connection 		1. Client sends: state=user|action|123

2. Zoho treats state as opaque data blob
3. User authorizes the connection
4. Redirect includes the exact value received:
state=user|action|123
(or consistently encoded as sent)
The Current Workaround (Suboptimal)
Important: The workarounds below only apply if you have control over the client application generating the OAuth request. If you're integrating with a third-party application that sets the state parameter (e.g., integration platforms, SaaS tools, enterprise software), you have no ability to modify the state value and therefore no workaround is available. You are completely blocked from completing the OAuth flow.
For developers who do control the client application, you must avoid pipe characters entirely: 
// Instead of using pipes as delimiters:
state = csrf_token + "|" + user_id + "|" + redirect_path;
// ❌ This breaks Zoho's authorization flow

// Developers must use alternative approaches:
state = csrf_token + "_SEP_" + user_id + "_SEP_" + redirect_path;
// or
state = base64_encode(json_encode({"csrf": token, "user": id, "path": path}));
// or
state = csrf_token; // Store other data server-side keyed by CSRF token
Problems with these workarounds:
  • Requires refactoring existing codebases that use pipe delimiters
  • Base64 encoding increases state parameter length significantly, risking URL length limits (particularly in older browsers and some enterprise proxies which enforce ~2000 character limits)
  • Server-side storage approach adds complexity, database overhead, and potential race conditions
  • Inconsistent with how the same code works with other OAuth providers (Google, Microsoft, etc.)
  • Developers may not discover this issue until production deployment
  • Custom delimiters (like _SEP_) are non-standard and may conflict with actual data values
What Should Happen Instead
Proposed Solution:
Zoho's authorization server should properly handle URL-encoded pipe characters (%7C) in the state parameter, as required by RFC 6749. The state value must be treated as an opaque data blob.
Technical Requirement: Treat state as a Data Blob
1. Input Accept %7C (and other encoded characters) as valid parts of the query string without triggering validation errors or WAF rules
2. Persistence Store the string exactly as received during the user's login/consent session—do not decode, parse, or transform
3. Output Append the exact string back to the redirect_uri without additional transformations that might strip or corrupt the delimiters
This approach:
  • Complies with RFC 6749's requirement to return "the exact value received"
  • Follows the same behavior as other major OAuth providers
  • Requires no changes from client applications
  • Unblocks third-party integrations that cannot modify their state format
Real-World Impact
This limitation affects any integration where:
  • Third-party applications set the state parameter and cannot be modified (integration platforms, SaaS connectors, enterprise software)
  • Multi-tenant applications need to encode tenant ID and return URL in state
  • CSRF protection implementations combine security tokens with application state
  • Single Sign-On flows need to preserve original request context
  • Migration projects from other OAuth providers that used pipe delimiters

Critical Blocker: When the state parameter originates from a third-party system outside your control, there is no workaround available. The integration is completely impossible until this is fixed.

Security Note: The state parameter is critical for CSRF protection in OAuth flows. Forcing developers to change their state encoding approach may inadvertently introduce security vulnerabilities if not handled carefully.

Request to Zoho Team

Can this be addressed in a future update?

This is a standards compliance issue that impacts developers integrating with Zoho's API. For those who control their client application, the current implementation forces unnecessary workarounds. For those integrating third-party applications, the situation is worse:

1. Custom development
Refactor code to avoid pipe characters, creating Zoho-specific OAuth handling 		2. Third-party integrations
No workaround possible - integration is completely blocked

Users should not be blocked from integrating with Zoho due to non-standard OAuth implementation.

Community Input Requested: Has anyone else encountered this issue? Are there other special characters that cause similar problems with Zoho's OAuth implementation?

    • Sticky Posts

    • Deprecation of SMS-based multi-factor authentication (MFA) mode

      Overview of SMS-based OTP MFA mode The SMS-based OTP MFA method involves the delivery of a one-time password to a user's mobile phone via SMS. The user receives the OTP on their mobile phone and enters it to sign into their account. SMS-based OTPs offer

    Nederlandse Hulpbronnen


      • Recent Topics

      • ZOHO Work Drive Back Up

        I am looking for a ZOHO Work Drive backup solution. Something that is cloud based. There's lots of these kinds of options for Google Drive and other providers, but I have not seen anything for WorkDrive. Any suggestions?

      • ZOHO Reports - Filter Logic?

        Hi, I need a way to apply filter logics such as ((1 AND 2) OR 3). All I can see as of now is a way to enter different AND filters in the respective filter column. But how can I add an OR filter? Any advice would be highly appreciated. Mark

      • Scanned Doc - selecting Item overwrites Rate

        I have a Vendor Invoice which was uploaded to Documents. I select Add To > New Bill. The OCR is actually quite good, but it is reading an Item Description instead of an Item Number. I remove the description and select the correct Item Number... and it

      • Recruit API search

        Hi all, Attempting to call the search api endpoint from Postman using the word element as mentioned in api docs Search Records - APIs | Online Help - Zoho Recruit When making the call to /v2/Candidates/search?word=Saudi receive response of { "code": "MANDATORY_NOT_FOUND",

      • Saving reading position + Keep screen on

        While Zoho Notebook is excellent for saving and annotating articles, its utility is severely limited by the lack of reading progress synchronization. On the Android app, if a user exits a long note after reading 50%, the app fails to save the position.

      • Multiple Vendor SKUs

        One of the big concerns we have with ZOHO Inventory is lack of Vendor Skus like many other inventory software packages offer. Being able to have multiple vendor skus for the same product would be HUGE! It would populate the appropriate vendor Sku for

      • Zoho LandingPage is integrated with Zoho One!

        Greetings to the Zoho One users out there! We're delighted to let you know that Zoho LandingPage is available in Zoho One too! With Zoho LandingPage, you can host custom-made landing pages, and persuade the visitors to dive deeper by making further clicks,

      • Android app sync problem - multiple devices have same problem

        Hello, I am having a problem with synchronization in the Android app. When I create a drawing, the data does not sync correctly—only a blank note is created without the drawing. I tested this on multiple devices, including phones and tablets, and the

      • How can i resend a campaign to only one of the recipients on the original campaign

        How can i resend a campaign to only one of the recipients on the original campaign ? Sincererly, Mike

      • How to show branch instead of org name on invoice template?

        Not sure why invoices are showing the org name not the branch name? I can insert the branch name using the ${ORGANIZATION.BRANCHNAME} placeholder, but then it isn't bold text anymore. Any other ideas?

      • Marketing Automation Requirements Questions

        I would like to set up a multi-email drip campaign- please see the structure below and confirm if I can achieve this set up in Zoho marketing automation. Where applicable, highlight gaps and workarounds. Thanks Drip email campaign- Can I create one drip

      • how to change the page signers see after signing a document in zoho sign

        Hello, How can I please change the page a signer sees after signing a document in Zoho Sign? I cannot seem to find it. As it is now, it shows a default landing page "return to Zoho Sign Home". Thanks!

      • Question about using custom_fields in Storefront Add-to-Cart API (error 2003 – required details)

        Hi everyone, I’m working with the Zoho Commerce Storefront API, specifically the Add to Cart endpoint: POST /storefront/api/v1/cart According to the documentation, this endpoint supports a custom_fields parameter for adding line-item custom data. I’m

      • Can a project be cloned?

        Good afternoon, greetings. I would like to ask if it's possible to clone a project in Microsoft Project. I found a way to do it using templates, but I'm not sure if there's a direct way to clone a project. Thank you in advance for your attention, and

      • Timesheet Tasks in Zoho Books: associate to service item

        How do we associate a service item to timesheet tasks in Zoho Books? For example: Joe spent 5 hours on project:task1 which is Service Item#1 (Income:Service1). When the invoice is issued thru the Project Invoice section, this is not available. When the

      • Task/Activity indicator in SalesPipeline overview has disappeared

        I Just logged in my ZOHO CRM first 2026 checking my salespipeline overview , Every record card used to show an indication that there was an open task (Yellow if the expiry date was close, red if the expiry date was today and grey when it had expired).

      • Tip #56- Accessibility Controls in Zoho Assist: Hearing- 'Insider Insights'

        As we begin the new year, it’s a great time to focus on making our tools more inclusive and accessible for everyone. Remote support often involves long hours in front of screens, varying lighting conditions, and users with diverse accessibility needs.

      • Zoho Desk Android app update: Table view for All Departments view, custom button

        Hello everyone! In the latest version(v2.9.25) of the Zoho Desk Android app update, we have introduced Table view for the 'All Departments' view in the ticket module. We also have supported an option that allows tickets in the Table view to be sorted

      • What's New - December 2025 | Zoho Backstage

        In December, Backstage introduced a focused set of updates that improve how you manage registrations, communicate with attendees, and track participation. These enhancements are designed to give organizers greater flexibility and clearer control across

      • Add multiple users to a task

        When I´m assigning a task it is almost always related to more than one person. Practical situation: When a client request some improvement the related department opens the task with the situation and people related to it as the client itself, the salesman

      • A Roundup of Zoho Sprints 2025

      • Sorting Custom Date in API isn't working w pagination limit

        How can we sort a custom field with DATE using pagination? Starting at page=1 then moving to page=2 with a limit of 10 each, its all messed up and even shows some of the same records as page 1? https://www.zohoapis.com/crm/v2/INVOICE_MODULE/search?criteria=(FM_Contact_ID:equals:1234)&sort_by=Invoice_Date&sort_order=desc&per_page=10&page='

      • SAP Business One(B1) integration is now live in Zoho Flow

        We’re excited to share that SAP Business One (B1) is now available in Zoho Flow! This means you can now build workflows that connect SAP B1 with other apps and automate routine processes without relying on custom code. Note: SAP Business One integration

      • Enhancement in Role and Profile mapping of agents in Sandbox

        Hello everyone! We have brought in a modification in the way users are mapped to a particular role and profile in Sandbox. What has changed? When agents are copied from production to Sandbox: If a user's current role and profile is available in Sandbox,

      • The reason I switched away from Zoho Notebook

        My main reason for switching to Zoho was driven by three core principles: moving away from US-based products, keeping my data within India as much as possible, and supporting Indian companies. With that intent, I’ve been actively de-Googling my digital

      • Decimal places settings for exchange rates

        Hello, We are facing issues while matching vendor payments with banking feeds. As we often import products/services exchange rate comes into play. Currently, ZOHO allows only six digits for decimal places. We feel that conversions like JPY to INR require

      • Zoho removed ability to see all Scheduled Reports!

        If you are not the owner of a scheduled report, Zoho recently removed the capability to see each scheduled report. As an admin who relies on seeing all scheduled reports being sent, this is a terrible update. Now I cannot see ANY scheduled reports...even the ones I am being sent!!  This should be a setting for admins to control.  This is a bad update.

      • Automate Backups

        This is a feature request. Consider adding an auto backup feature. Where when you turn it on, it will auto backup on the 15-day schedule. For additional consideration, allow for the export of module data via API calls. Thank you for your consideration.

      • GCLID and Zoho Bookings

        Is there anyway to embed a Zoho Bookings signup on a landing page and pass the GCLID information? More specifically, can this be done using auto-tagging and not manual tagging the GCLID? I know Zappier has an integration to do this but is there a better

      • Merge Items

        Is there a work around for merging items? We currently have three names for one item, all have had a transaction associated so there is no deleting (just deactivating, which doesn't really help. It still appears so people are continuing to use it). I also can't assign inventory tracking to items used in past transactions, which I don't understand, this is an important feature moving forward.. It would be nice to merge into one item and be able to track inventory. Let me know if this is possible.

      • Create PO from an invoice

        We are a hardware and software sales company which receives orders over the internet. We drop ship most of our products from a warehouse outside of our company. Our orders get sync'd into Zoho from our store via onesaas as invoices. It would be great

      • Blueprint or Validation Rules for Invoices in Zoho Books

        Can I implement Blueprint or Validation Rules for Invoices in Zoho Books? Example, use case could be, Agent confirms from client that payment is done, but bank only syncs transactions tomorrow. in this case, Agent can update invoice status to done, and

      • Resetting auto-number on new year

        Hi everyone! We have an auto-number with prefix "D{YYYY}-", it generates numbers like D2025-1, D2025-2, etc... How can we have it auto-reset at the beginning of the next year, so that it goes to D2026-1? Thanks!

      • The Social Wall: December 2025

        Hello everyone! As we wrap up the final edition of the Social Wall for 2025, it’s the perfect time to look at what went live during December. QR code generator From paying for coffee to scanning metro tickets, QR codes are everywhere and have made everyday

      • Custom AI solutions with QuickML for Zoho CRM

        Hello everyone, Earlier, we introduced Custom AI Solutions in CRM that let you access QuickML for your custom AI needs. Building on that foundation, we’ve now enabled a deeper integration: QuickML models can be seamlessly integrated into CRM, and surface

      • Helper Functions and DRY principle

        Hello everyone, I believe Deluge should be able to use 'Helper functions' inside the main function. I know I can create different standalones, but this is not helpful and confusing. I don't want 10000 different standalones, and I dont want to have to

      • Introducing workflow automation for the Products module

        Greetings, I hope all of you are doing well. We're happy to announce a few recent enhancements we've made to Bigin's Products module. The Products module in Bigin now supports Workflows, enabling you to automate routine actions. Along with this update,

      • Power up your Kiosk Studio with Real-Time Data Capture, Client Scripts & More!

        Hello Everyone, We’re thrilled to announce a powerful set of enhancements to Kiosk Studio in Zoho CRM. These new updates give you more flexibility, faster record handling, and real-time data capture, making your Kiosk flows smarter and more efficient

      • Zia Formula Expression Generator for Formula fields

        Hello everyone! Formula fields are super useful when you want your CRM to calculate things for you but writing the expression is where most people slow down. You know what you want, but you’re not fully sure which function to use, how the syntax should

      • Issue with Zoho Creator Form Full-Screen View in CRM Related List Integration

        Hi Team, We have created a custom application in Zoho Creator and integrated it into Zoho CRM as a related list under the Vendor module, which we have renamed as Consignors. Within the Creator application, there is a form named “Pickup Request.” Inside

      • Next Page