CVE-2026-27197: Sentry Improper Authentication On SAML SSO Vulnerability

CRITICAL
Advisory Identifier: GHSA-ggmg-cqg6-j45g
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CVSS 9.1
CWE-287
Published
Advisory Summary

CVE-2026-27197 is a CRITICAL (CVSS 9.1) improper authentication on saml sso vulnerability (CWE-287: Improper Authentication) affecting Sentry libraries in the PyPI ecosystem. The issue involves improper authentication on saml sso process allows user identity linking. Remediation is available in the latest vendor maintenance releases.

CVE-2026-27197 at a Glance

CVE Identifier CVE-2026-27197
GHSA Identifier GHSA-ggmg-cqg6-j45g
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-287: Improper Authentication
Affected Product Sentry
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-27197

To remediate this vulnerability, upgrade all affected Sentry dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

sentry fixed: Latest secure release 
pip install sentry>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show sentry

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-27197, inspect your installed packages using pip:

pip show sentry

Analyze the terminal output to locate any version of Sentry in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show sentry command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In Sentry, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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 = False). - A malicious user has existing access and permissions to modify SSO settings for another organization in your multo-organization instance. ### Patches - [Sentry SaaS](https://sentry.io/): The fix was deployed on February 18, 2026. No action is required. - [Self-Hosted Sentry](https://github.com/getsentry/self-hosted): 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](https://sentry.io/settings/account/security/) page. For step-by-step details, please see our [helpdesk article](https://sentry.zendesk.com/hc/en-us/articles/46773315774235-How-do-I-enable-two-factor-authentication-2FA-on-my-Sentry-account).

CVE-2026-27197 Affected Sentry Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
sentry
pypi/sentry
PyPI
≥ 21.12.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/getsentry/sentry/security/advisories/GHSA-ggmg-cqg6-j45g
NVD — CVE-2026-27197 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27197
Sentry Source Repository REPOSITORY
https://github.com/getsentry/sentry/pull/108458
Sentry Source Repository REPOSITORY
https://github.com/getsentry/sentry

Frequently Asked Questions

What is CVE-2026-27197?
CVE-2026-27197 is a security vulnerability in Sentry involving Improper authentication on SAML SSO process allows user identity linking under CWE-287: Improper Authentication.
Which Sentry versions are affected?
Affected versions include releases prior to current release patches across affected packages: sentry.
What version fixes CVE-2026-27197?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is sentry affected?
Yes, sentry is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-27197?
CVE-2026-27197 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-27197?
CVE-2026-27197 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check PyPI dependencies for CVE-2026-27197?
Run the dependency tree command: 'pip show sentry'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-ggmg-cqg6-j45g",
  "modified" : "2026-04-17T21:25:37Z",
  "published" : "2026-04-17T21:25:37Z",
  "aliases" : [ "CVE-2026-27197" ],
  "summary" : "Sentry: Improper authentication on SAML SSO process allows user identity linking",
  "details" : "### Impact\nA critical vulnerability was discovered in the SAML SSO implementation of Sentry. It was reported to us via our private bug bounty program.\n\nThe 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.\n\nFor self-hosted users, you are only vulnerable if the following conditions are met:\n- You have more than one organization configured (SENTRY_SINGLE_ORGANIZATION = False).\n- A malicious user has existing access and permissions to modify SSO settings for another organization in your multo-organization instance. \n\n### Patches\n- [Sentry SaaS](https://sentry.io/): The fix was deployed on February 18, 2026. No action is required.\n- [Self-Hosted Sentry](https://github.com/getsentry/self-hosted): 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.\n\n### Workarounds\nUser 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.\n\nYou can manage your two-factor authentication settings on your Account Settings > [Security](https://sentry.io/settings/account/security/) page. For step-by-step details, please see our [helpdesk article](https://sentry.zendesk.com/hc/en-us/articles/46773315774235-How-do-I-enable-two-factor-authentication-2FA-on-my-Sentry-account).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "sentry"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "21.12.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "< 26.2.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/getsentry/sentry/security/advisories/GHSA-ggmg-cqg6-j45g"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27197"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/getsentry/sentry/pull/108458"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/getsentry/sentry"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-17T21:25:37Z",
    "nvd_published_at" : "2026-02-21T05:17:29Z"
  }
}