CVE-2026-42354

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.

Users can manage their two-factor authentication settings through Account Settings > Security page. For step-by-step details, please see the Sentry helpdesk article.

Resources

• https://github.com/getsentry/sentry/pull/113720

Please note that this is distinct vulnerability from the similar https://github.com/getsentry/sentry/security/advisories/GHSA-7pq6-v88g-wf3w from 2025.

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

Self-hosted users are only vulnerable if the following conditions are met:

• They 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 their multi-organization instance.

CVE-2026-42354 has a CVSS score of 9.1 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (26.4.1); upgrading removes the vulnerable code path.

Kodem intelligence

• Sentry SaaS: The fix was deployed in April. No action is required.
• Self-Hosted Sentry: If only a single organization is allowed (SENTRY_SINGLE_ORGANIZATION = True), then no action is needed. Sentry recommends upgrading to version 26.4.1 or higher.

1. What is CVE-2026-42354? CVE-2026-42354 is a critical-severity security vulnerability in sentry (pip), affecting versions >= 21.12.0, <= 26.4.0. It is fixed in 26.4.1.
2. How severe is CVE-2026-42354? CVE-2026-42354 has a CVSS score of 9.1 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of sentry are affected by CVE-2026-42354? sentry (pip) versions >= 21.12.0, <= 26.4.0 is affected.
4. Is there a fix for CVE-2026-42354? Yes. CVE-2026-42354 is fixed in 26.4.1. Upgrade to this version or later.
5. Is CVE-2026-42354 exploitable, and should I be worried? Whether CVE-2026-42354 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-42354 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-42354? Upgrade sentry to 26.4.1 or later.