---
id: CVE-2026-3632
title: >-
  Libsoup: libsoup: http smuggling and server-side request forgery via malformed
  hostnames
summary: >-
  A flaw was found in libsoup, a library used by applications to send network
  requests. This vulnerability occurs because libsoup does not properly validate
  hostnames, allowing special characters to be injected into HTTP headers. A
  remote …
severity: low
cvss: 3.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L'
cvssSource: cna
cwe:
  - CWE-1286
vendor: Red Hat
product: libsoup3
affected:
  - libsoup3 (all versions)
  - libsoup
  - libsoup (all versions)
  - libsoup (all versions)
  - libsoup (all versions)
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-03-17T13:01:56.752811Z'
published: '2026-03-17'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T18:37:57.900Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-3632'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-3632'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2445127'
    label: RHBZ#2445127
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/issues/483'
tags:
  - cve.org
epss: 0.0022
epssPercentile: 0.12625
ingestedAt: '2026-11-06T19:01:36.626Z'
---

## Overview

A flaw was found in libsoup, a library used by applications to send network requests. This vulnerability occurs because libsoup does not properly validate hostnames, allowing special characters to be injected into HTTP headers. A remote attacker could exploit this to perform HTTP smuggling, where they can send hidden, malicious requests alongside legitimate ones. In certain situations, this could lead to Server-Side Request Forgery (SSRF), enabling an attacker to force the server to make unauthorized requests to other internal or external systems. The impact is low, as SoupServer is not actually used in internet infrastructure.

## Affected

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

## Remediation

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

### Workarounds

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.