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TI-2026-39265 Aliases CVE-2026-54387GHSA-9667-7p67-2364

Tinyproxy - HTTP Request Smuggling via CL/TE Desynchronization

Priority MEDIUM 48CWE-444Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Tinyproxy through 1.11.3, fixed in commit ff45d3b, fails to reconcile conflicting Content-Length and Transfer-Encoding: chunked headers, forwarding both verbatim to the backend while using Content-Length to determine how many request body bytes to consume. Remote attackers can desynchronize the proxy and backend parser state, allowing injection of arbitrary HTTP requests to the backend to enable cache poisoning, access control bypass, and request hijacking.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00439 38th percentileScored 2026-11-07
Fix Fixed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
tinyproxytinyproxyup to 1.11.3—Patch availableCNA
  • tinyproxy Vendortinyproxy Affected up to 1.11.3 Fixed in — Patch available CNA

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-54387
  2. 2026-10-03 Alias added: GHSA-9667-7p67-2364
  3. 2026-10-25 EPSS moved to the below the 50th percentile

References

Patch 1

Other 2

  • TI-2023-27093 Use after free in Tinyproxy CVSS 3.1CRITICAL 9.8
  • TI-2026-39266 Tinyproxy - HTTP Request Smuggling via Duplicate Content-Length Headers CVSS 4.0CRITICAL 9.3
  • TI-2001-00129 Buffer overflow in Tinyproxy HTTP proxy 1.3.3 and earlier allows remote attackers to… CVSS 2.0HIGH 10.0
  • TI-2026-03412 tinyproxy Integer Overflow in HTTP Chunked Transfer-Encoding Parser Leading to Denial of Service CVSS 4.0HIGH 8.7
  • TI-2026-39882 Tinyproxy - Stathost Detection Bypass via Host Header Manipulation CVSS 4.0HIGH 8.8
  • TI-2002-00822 tinyproxy HTTP proxy 1.5.0, 1.4.3, and earlier allows remote attackers to execute… CVSS 2.0HIGH 7.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences