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Sentry's improper authentication on SAML SSO process allows user identity linking

Critical severity GitHub Reviewed Published Apr 22, 2026 in getsentry/sentry • Updated Apr 30, 2026

Package

sentry (pip)

Affected versions

>= 21.12.0, <= 26.4.0

Patched versions

26.4.1

Description

Impact

A critical vulnerability was discovered in the SAML SSO implementation of Sentry. It was reported to us via Sentry's private bug bounty program.

The vulnerability allows an attacker to take over any user account by using a malicious SAML Identity Provider and another organization on the same Sentry instance. The victim email address must be known in order to exploit this vulnerability.

Self-hosted users are only vulnerable if the following conditions are met:

  • They have more than one organization configured (SENTRY_SINGLE_ORGANIZATION = False).
  • A malicious user has existing access and permissions to modify SSO settings for another organization in their multi-organization instance.

Patches

  • Sentry SaaS: The fix was deployed in April. No action is required.
  • Self-Hosted Sentry: If only a single organization is allowed (SENTRY_SINGLE_ORGANIZATION = True), then no action is needed. Sentry recommends upgrading to version 26.4.1 or higher.

Workarounds

User account-based two-factor authentication prevents an attacker from being able to complete authentication with a victim's user account. Organization administrators cannot do this on a user's behalf, this requires individual users to ensure 2FA has been enabled for their account.

Users can manage their two-factor authentication settings through Account Settings > Security page. For step-by-step details, please see the Sentry helpdesk article.

Resources

Please note that this is distinct vulnerability from the similar GHSA-7pq6-v88g-wf3w from 2025.

References

@geoffg-sentry geoffg-sentry published to getsentry/sentry Apr 22, 2026
Published to the GitHub Advisory Database Apr 30, 2026
Reviewed Apr 30, 2026
Last updated Apr 30, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS score

Weaknesses

Authentication Bypass by Spoofing

This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. Learn more on MITRE.

CVE ID

CVE-2026-42354

GHSA ID

GHSA-rcmw-7mc7-3rj7

Source code

Credits

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