dbcve.org
Information ExposureWeakness · CWE-200

CVE-2026-9349

MEDIUM · 5.3 CVSS v3.1 Published 2026-05-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability was determined in calcom cal.diy up to 4.9.4. Affected by this issue is the function getServerSideProps of the file apps/web/modules/bookings/views/bookings-single-view.getServerSideProps.tsx of the component Generic React API. This manipulation of the argument cancelledBy/rescheduledBy causes information disclosure. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure but did not respond in any way.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A server-side information disclosure vulnerability exists in calcom cal.diy up to v4.9.4 within the getServerSideProps function of bookings-single-view. The function improperly handles the cancelledBy and rescheduledBy arguments, allowing remote attackers to manipulate these parameters to access sensitive booking information without proper authorization.

MitigationImplement strict input validation and authorization checks on the cancelledBy/rescheduledBy parameters in getServerSideProps to ensure users can only access booking data they are authorized to view. Upgrade to version 4.9.5 or later if available.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Cal.com installation version
    Check your package.json file or run a package manager command (npm list @calcom/app-sdk or equivalent) to determine the installed Cal.com version
    Affected if The installed version falls within any vulnerable version range for this CVE
  2. Locate the bookings-single-view page component
    Search the codebase for the bookings-single-view page file, typically found in the pages/bookings directory or similar routing structure in a Cal.com deployment
    Affected if The bookings-single-view page component exists in the deployment and is accessible to users
  3. Inspect getServerSideProps for missing authorization checks
    Open the bookings-single-view page file and examine the getServerSideProps function, specifically looking for how cancelledBy and rescheduledBy query parameters or props are handled
    Affected if The getServerSideProps function processes cancelledBy or rescheduledBy parameters without verifying user authorization to access that booking data
  4. Check if booking data is returned without ownership verification
    Review the getServerSideProps return value and verify whether the booking data is filtered or validated to ensure the requesting user owns or has access to the booking
    Affected if The SSR response includes booking details (such as cancelledBy or rescheduledBy fields) for bookings the user does not own or is not authorized to view
  5. Test parameter manipulation in a non-production environment
    If possible, access the bookings-single-view page with different cancelledBy or rescheduledBy query parameter values and observe whether sensitive booking information from other users is returned
    Affected if Manipulating these parameters reveals booking information that belongs to other users or events

A user is affected if they run a Cal.com deployment where the bookings-single-view getServerSideProps function returns booking details without properly validating that the requesting user is authorized to view those specific bookings when cancelledBy or rescheduledBy parameters are supplied.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict input validation and authorization checks on the cancelledBy/rescheduledBy parameters in getServerSideProps to ensure users can only access booking data they are authorized to view. Upgrade to version 4.9.5 or later if available.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-9349 in production — separate from our analysis above.

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What this is

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