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Improper authentication on SAML SSO process allows user identity linking

Critical
geoffg-sentry published GHSA-ggmg-cqg6-j45g Feb 18, 2026

Package

pip sentry (pip)

Affected versions

>= 21.12.0, < 26.2.0

Patched versions

26.2.0

Description

Impact

A critical vulnerability was discovered in the SAML SSO implementation of Sentry. It was reported to us via our 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.

For self-hosted users, you are only vulnerable if the following conditions are met:

  • You have more than one organization configured (SENTRY_SINGLE_ORGANIZATION = True).
  • A malicious user has existing access and permissions to modify SSO settings for another organization in your multo-organization instance.

Patches

  • Sentry SaaS: The fix was deployed on February 18, 2026. No action is required.
  • Self-Hosted Sentry: If only a single organization is allowed (SENTRY_SINGLE_ORGANIZATION = True), then no action is needed. We recommend upgrading to version 26.2.0 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.

You can manage your two-factor authentication settings on your Account Settings > Security page. For step-by-step details, please see our helpdesk article.

References

#108458

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

CVE ID

CVE-2026-27197

Weaknesses

Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Learn more on MITRE.

Credits