---
id: CVE-2026-12548
title: 'Libsoup: heap out-of-bounds read in libsoup due to integer truncation'
summary: >-
  A heap out-of-bounds read flaw was found in libsoup. When parsing multipart
  HTTP messages, an integer type mismatch between the caller and
  soup_headers_parse() can cause the length parameter to be incorrectly
  truncated, leading to a heap…
severity: medium
cvss: 4.2
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-125
vendor: Red Hat
product: libsoup3
affected:
  - libsoup3 (all versions)
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-07-23T14:19:42.070603Z'
exploitAvailable: true
published: '2026-07-21'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T17:02:46.773Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-12548'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-12548'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2489996'
    label: RHBZ#2489996
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/work_items/512'
tags:
  - cve.org
  - exploit-available
epss: 0.00254
epssPercentile: 0.17103
ingestedAt: '2026-11-05T22:38:31.417Z'
---

## Overview

A heap out-of-bounds read flaw was found in libsoup. When parsing multipart HTTP messages, an integer type mismatch between the caller and soup_headers_parse() can cause the length parameter to be incorrectly truncated, leading to a heap buffer over-read. A remote attacker could use this flaw to crash an application using libsoup or potentially disclose heap memory contents.

## Affected

- `libsoup3 (all versions)`

## Remediation

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