---
id: CVE-2026-54387
title: Tinyproxy - HTTP Request Smuggling via CL/TE Desynchronization
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 bod…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-444
vendor: tinyproxy
product: tinyproxy
affected:
  - tinyproxy <= 1.11.3
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-06-18T13:10:38.925525Z'
published: '2026-06-17'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T14:05:19.774Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-54387'
references:
  - url: 'https://github.com/tinyproxy/tinyproxy/issues/609'
    label: Researcher Pull Request
  - url: 'https://github.com/tinyproxy/tinyproxy/pull/610'
    label: Maintainer Pull Request
  - url: >-
      https://github.com/tinyproxy/tinyproxy/commit/ff45d3bf0e61d0f8ed97ab379d3047f04eb67521
    label: Patch Commit
  - url: >-
      https://www.vulncheck.com/advisories/tinyproxy-http-request-smuggling-via-cl-te-desynchronization
tags:
  - cve.org
epss: 0.00439
epssPercentile: 0.38377
ingestedAt: '2026-11-08T14:51:22.374Z'
---

## Overview

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.

## Affected

- `tinyproxy <= 1.11.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.