---
id: CVE-2026-2708
title: 'Libsoup: libsoup: http request smuggling via duplicate content-length headers'
summary: >-
  A request smuggling vulnerability exists in libsoup's HTTP/1 header parsing
  logic. The soup_message_headers_append_common() function in
  libsoup/soup-message-headers.c unconditionally appends each header value
  without validating for dupli…
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-444
vendor: Red Hat
product: libsoup3
affected:
  - libsoup3 (all versions)
  - libsoup (all versions)
  - libsoup (all versions)
  - libsoup (all versions)
  - libsoup (all versions)
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-04-24T14:53:37.912115Z'
published: '2026-04-23'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T18:23:22.965Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-2708'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-2708'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2440743'
    label: RHBZ#2440743
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/issues/500'
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/513'
tags:
  - cve.org
epss: 0.00321
epssPercentile: 0.25291
ingestedAt: '2026-11-06T19:01:36.637Z'
---

## Overview

A request smuggling vulnerability exists in libsoup's HTTP/1 header parsing logic. The soup_message_headers_append_common() function in libsoup/soup-message-headers.c unconditionally appends each header value without validating for duplicate or conflicting Content-Length fields. This allows an attacker to send HTTP requests containing multiple Content-Length headers with differing values.

## Affected

- `libsoup3 (all versions)`
- `libsoup (all versions)`
- `libsoup (all versions)`
- `libsoup (all versions)`
- `libsoup (all versions)`

## Remediation

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