CVE-2026-42354 Sentry: Improper authentication on SAML SSO process allows user identity linking

What is CVE-2026-42354?

CVE-2026-42354 is a critical authentication bypass vulnerability in getsentry sentry, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Sentry is an error tracking and performance monitoring tool. From version 21.12.0 to before version 26.4.1, a critical vulnerability was discovered in the SAML SSO implementation of Sentry. 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. This issue has been patched in version 26.4.1.

Weakness: CWE-290

Which versions are affected by CVE-2026-42354?

3 open source packages ship an affected version, including sentry. It affects 1 product.

Products include Sentry Sentry.

How do I fix CVE-2026-42354?

Upgrade sentry to 26.4.1 or later.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-42354 being exploited?

There is no known exploitation of CVE-2026-42354 in the wild and no public exploit code.

Other vulnerabilities in getsentry sentry

• CVE-2026-27197 Sentry: Improper Authentication on SAML SSO process allows user identity linking Critical 9.1
• CVE-2021-47935 Sentry 8.2.0 Remote Code Execution via Pickle Deserialization High 8.7
• CVE-2023-39349 Sentry vulnerable to privilege escalation via ApiTokensEndpoint High 8.1
• CVE-2023-36826 Sentry vulnerable to improper authorization on debug and artifact file downloads High 7.7
• CVE-2026-52794 Sentry: Inefficient Regular Expression Complexity in sentry High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ECHO-ea50-90d1-d8b8, GHSA-rcmw-7mc7-3rj7, PYSEC-2026-534.