CVE-2026-27197: Sentry: Improper authentication on SAML SSO process allows user identity linking

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.7%, percentile 51: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 51% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes sentry (PyPI) >= 21.12.0, < 26.2.0, no fixed version listed. Check your lockfile, including transitive dependencies.

What it is

Sentry is a developer-first error tracking and performance monitoring tool. Versions 21.12.0 through 26.1.0 have a critical vulnerability in its SAML SSO implementation which allows an attacker to take over any user account by using a malicious SAML Identity Provider and another organization on the same Sentry instance. Self-hosted users are only at risk if the following criteria is met: ore than one organizations are configured (SENTRYSINGLEORGANIZATION = True), or malicious user has existing access and permissions to modify SSO settings for another organization in a multo-organization instance. This issue has been fixed in version 26.2.0. To workaround this issue, implement user account-based two-factor authentication to prevent 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.

From the GitHub advisory

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 (SENTRYSINGLEORGANIZATION = False). - 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 (SENTRYSINGLEORGANIZATION = 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.

Weakness type: CWE-287.

Product: sentry (PyPI) · Assigned by: GitHub_M · Published: 2026-02-21

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.65% probability of exploitation activity in the next 30 days; percentile 51.

Timeline

• 2026-02-21 — CVE record published by GitHub_M
• 2026-02-24 — CVE record last updated
• 2026-04-17 — GitHub-reviewed advisory GHSA-ggmg-cqg6-j45g published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-ggmg-cqg6-j45g github.com
2. CVE.org record CVE-2026-27197 cve.org
3. NVD entry CVE-2026-27197 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

Critical PyPI advisories · Today’s Security Digest