---
id: CVE-2026-15714
title: >-
  Libsoup: soupmultipartinputstream: libsoup: out-of-bounds read in
  soup_multipart_input_stream_read_headers via an oversized multipart boundary
  string
summary: >-
  An out-of-bounds read vulnerability was found in libsoup's multipart
  processing subsystem. The flaw exists in the
  soup_multipart_input_stream_read_headers() function inside
  soup-multipart-input-stream.c, which does not adequately restric…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-125
vendor: Red Hat
product: libsoup3
affected:
  - libsoup3 (all versions)
  - libsoup
  - libsoup
  - libsoup (all versions)
  - libsoup (all versions)
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-07-15T14:09:41.025861Z'
exploitAvailable: true
published: '2026-07-14'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T16:42:50.685Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-15714'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-15714'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2499942'
    label: RHBZ#2499942
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/work_items/542'
tags:
  - cve.org
  - exploit-available
epss: 0.0039
epssPercentile: 0.33352
ingestedAt: '2026-11-05T22:38:31.399Z'
---

## Overview

An out-of-bounds read vulnerability was found in libsoup's multipart processing subsystem. The flaw exists in the soup_multipart_input_stream_read_headers() function inside soup-multipart-input-stream.c, which does not adequately restrict or validate the size of incoming multipart boundary strings. When processing a crafted HTTP response containing a malformed or oversized boundary parameter, the internal stream reader reads past the allocated buffer bounds. A remote, unauthenticated attacker can exploit this behavior to cause a service denial (DoS) through application failure or potentially read fragments of unauthorized memory metadata.

## Affected

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

## Remediation

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

### Workarounds

To mitigate this issue, restrict network access to applications that utilize libsoup for processing multipart messages from untrusted sources. Implement firewall rules to limit incoming connections to only trusted clients, thereby reducing the attack surface. If the vulnerable component is part of a service, ensure that the service is not exposed to untrusted networks.