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
    • Recent Topics

    • Spreadsheet View click & focus issue in Arabic (RTL) localization

      Hello Zoho Support Team, I am facing an issue in Zoho Creator Spreadsheet View when using Arabic localization (RTL). Scenario: My app supports English (LTR) and Arabic (RTL). I created a Spreadsheet View for a form. In English, everything works correctly.
    • Customer address in Zoho Bookings

      Hello,  Is it possible to add customer address information to the Zoho bookings appointment screen? Or have it pull that information automatically from the CRM? We are wanting to use this as a field management software but it is difficult to pull the address from multiple sources when it would be ideal to have a clickable address on the appointment screen that opens up the user's maps.  It would also be advantageous for the "list view" to show appointment times instead of just duration and booking
    • Ghost email notification on a form

      Hello, We have recently encountered an error where I can not see a email notification set up for a form which I am currently the owner, although neither the form nor the notification were created by me. However, neither can the Super Admin access the
    • bulk edit records and run internal logic

      hi there is few logics in manner "it this than that" logics work well when i edit entry openning it one by one (via workflow "on add/edit - on success" , for custom field "on update/on user input") but when i try bulk edit records - logic does not work.  how can i turn on logic to work as programmed - for mass editing records via bulk edit?
    • Bulk bank rule creatioin

      Hi team, I am exploring Option to create a multiple bank rule. Could please suggest the option to implement this?
    • Limitations on editing a message in Cliq

      Hi I've checked the documentations and there's no mention of how many times a message can be edited. When trying with code, I get various numbers such as ~1000 edits or so. Please mention if there's a limit on how many times one can change a message via
    • email address autocomplete

      Is there a way to eliminate certain addresses from showing up in auto complete when entering an address? Many old and unused addresses currently show up, many of which I would like to get rid of. Thanks
    • How to use MAIL without Dashboard?

      Whenever I open Mail, it opens Dashboard. This makes Mail area very small and also I cannot manage Folders (like delete/rename) etc. I want to know if there is any way to open only Mail apps and not the Dashboard.
    • How can i download and secure all my mails from the archive folders?

      Hi, i would like to download all my mails from my archive folders and secure it on my external HDD. Is this possible? Thx. amir
    • How to open filtered report in popup using Zoho Creator Deluge?

      First report: There is so many records in Report, If I click one record, pop up is occur. Second report (Pop up): there is also so many record data, and this pop up is also Report, not Form. First report: It has got "Sales Order" field. when I click any
    • Can you default reports/charts to report the current week?

      Our data table maintains two years of data. Management wants certain report to automatically filter the report to the latest calendar week. I know I can do this manually with filters but I want the report to automatically default to the latest calendar
    • Rendering PDF to view on page

      My company upload lots of PDF files onto Zoho. But every time we open it, it downloads the file instead of viewing it on the web page. Does Zoho allow uploaded PDF files to be rendered to view on web page yet? I've been trying to use <embed> or <object> but it cannot be loaded.  (similar thread: https://help.zoho.com/portal/community/topic/how-to-open-a-pdf-file-of-a-view-in-preview-mode)
    • Overlapping Reports in Dashboards

      It's rare, but occasionally it would be a good feature if I were able to overlap reports, either fully or partially in the Dashboards. Also, then having the ability to move objects to the front or rear, or make them transparent/translucent would be good
    • Feature request - pin or flag note

      Hi, It would be great if you could either pin or flag one or more notes so that they remain visible when there are a bunch of notes and some get hidden in the list. Sometimes you are looking for a particular name that gets lost in a bunch of less important
    • Admin guide: Handling Mailbox Settings for better user management

      Managing day-to-day email scenarios, such as supporting users with multiple email addresses, ensuring uninterrupted email access during employee absences, enabling secure mailbox sharing, and enforcing organizational security and compliance, can be challenging
    • Cisco Webex Calling Intergration

      Hi Guys, Our organisation is looking at a move from Salesforce to Zoho. We have found there is no support for Cisco Webex Calling however? Is there a way to enable this or are there any apps which can provide this? Thanks!
    • Designing a practical Zoho setup for a small business: lessons from a real implementation

      I recently finished setting up a Zoho-based operating system for a small but growing consumer beauty business (GlowAtHomeBeauty), and I wanted to share a practical takeaway for other founders and implementers. The business wasn’t failing because of lack
    • DKIM (Marketing emails) UNVERIFIED (Zoho One)

      I'm having a problem with Zoho One verifying my Marketing Email DKIM Record for MYFINISHERPHOTOS.COM. I have removed and re-entered the ownership, DKIM (Transactional emails), SPF and Marketing DKIM and all of them come back verified except the DKIM (Marketing
    • Zoho Recruit Community Meet-up - India

      Namaste, India. 🙏🏼 The Zoho Recruit team is hitting the road—and we 're absolutely excited behind the scenes. Join us for the Zoho Recruit India Meet-up 2026, a morning designed to make your recruiting life easier (and a lot more effective). Date City
    • Generate a Zoho Sign link

      From time to time I get a response "I never received your you e-document for electronic signature" is there a way to generate a Zoho Sign link to share.
    • Is it possible to create a word cloud chart in ZoHo Analystics?

      Hi there, I have a volume of transaction text that I would like to analyse using word cloud (or other approcah to detect and present word frequency in a dataset). For example, I have 50,000 records describing menu items in restaurants. I want to be able
    • How to Fix the Corrupted Outlook 2019 .pst file on Windows safely?

      There are multiple reasons to get corrupted PST files (due to a power failure, system crash, or forced shutdown) and several other reasons. If You are using this ScanePST.EXE Microsoft inbuilt recovery tool, it only supports the minor corruption issue
    • [Webinar] A recap of Zoho Writer in 2025

      Hi Zoho Writer users, We're excited to announce Zoho Writer's webinar for January 2026: A recap of Zoho Writer in 2025. This webinar will provide a recap of the features and enhancements we added in 2025 to enhance your productivity. Choose your preferred
    • How to drag row(s) or column(s)?

      Hi. Selecting a row or column and then dragging it to a new position does not seem to work. Am i missing something or this is just not possible in Zoho Sheet? Cheers, Jay
    • Building Toppings #5 - Creating and configuring custom service connections in Bigin Toppings

      Hello Biginners, Integrating Bigin with external applications extends its capabilities and enables customized functionalities. In our last post, we saw how to create a default service connection. Today, we'll see how to create a custom service connection
    • Optimising CRM-Projects workflows to manage requests, using Forms as an intermediary

      Is it possible to create a workflow between three apps with traceability between them all? We send information from Zoho CRM Deals over to Zoho Projects for project management and execution. We have used a lookup of sorts to create tasks in the past,
    • Marketing Tip #15: Rank better with keyword-rich URLs for product pages

      Your product page URL is a small detail that can make a surprisingly big difference. Clean, readable URLs help in two ways: They’re easier for customers to trust and remember (no one likes clicking a link that looks messy or random). They help search
    • Conditional fields when converting a Lead and creating a Deal

      Hi, On my Deal page I have a field which has a rule against it. Depending on the value entered, depends on which further fields are displayed. When I convert a Lead and select for a Deal to be created as well, all fields are shown, regardless of the value
    • ATE Session on Payment Gateways: Our experts are live now. Post your questions now!

      Hello everyone, Our experts are all excited to answer all your questions related to payment workflows. Please feel free to join this session and learn more about this topic. If you have a query at anytime, please post them here.
    • Upload data deleted all Zoho form data that we manage

      Good morning. Let me introduce myself, I'm Iky from Indonesia. I'm experiencing an error or problem using Zoho Forms. I manage Zoho Forms, but I previously encountered an error when I misclicked the delete button in the upload format. It apparently deleted
    • ZOHO FORMにURL表示ができない

      初心者です。 ZOHO FORM で宿泊者名簿を作っています。 ゲストが、URLをクリックするとStripeで支払いができるようにURLを表示をしたいのですが、 上手くできません。 やり方が分かる方、ぜひ教えてください。
    • Custom module - change from autonumber to name

      I fear I know the answer to this already, but thought I'd ask the question. I created a custom module and instead of having a name as being the primary field, I changed it to an auto-number. I didn't realise that all searches would only show this reference.
    • No Automatic Spacing on the Notebook App?

      When I'm adding to notes on the app, I have to add spaces between words myself, rather than it automatically doing it. All my other apps add spacing, so it must be something with Zoho. Is there a setting I need to change, or something else I can do so
    • Holidays - Cannot Enter Two Holidays on Same Day

      I have a fairly common setup, where part-time employees receive 1/2 day's pay on a holiday and full-time employees receive a full day's pay. Historically, I've been able to accommodate this by entering two separate holidays, one that covers full-time
    • Zoho Bookings and Survey Integration through Flow

      I am trying to set up flows where once an appointment is marked as completed in Zoho Bookings, the applicable survey form would be sent to the customer. Problem is, I cannot customise flows wherein if Consultation A is completed, Survey Form A would be
    • Campaigns set up and execution assistance

      Hello Community, Can someone recommend a professional who can assist with the completion of my set up and deployment of Campaigns? Looking for a person or company that is not going to ask for big dollars up-front without a guarantee of performance to
    • Zobot with Plugs

      Hello, I am having a problem with Zobot using Plugs. Here is my current flow: When I run the flow, I should immediately see the messages from the initial cards (Send Message cards), then after running the plug, and finally, see the messages after the
    • Kaizen #223 - File Manager in CRM Widget Using ZRC Methods

      Hello, CRM Wizards! Here is what we are improving this week with Kaizen. we will explore the new ZRC (Zoho Request Client) introduced in Widget SDK v1.5, and learn how to use it to build a Related List Widget that integrates with Zoho WorkDrive. It helps
    • Remove Powered by Zoho at the footer

      Hi, I've read two past tickets regarding this but it seems that the instructions given are outdated. I assume the layout keeps on changing, which makes it frustrating for me to search high and low. Please let me know how exactly do I do this now? Th
    • Error AS101 when adding new email alias

      Hi, I am trying to add apple@(mydomain).com The error AS101 is shown while I try to add the alias.
    • Next Page