---
id: CVE-2026-15712
title: >-
  Soupclientmessageiohttp2: libsoup3: libsoup: http/2 goaway frame parsing heap
  buffer over-read via invalid nul-termination assumption
summary: >-
  A heap buffer over-read vulnerability was discovered in libsoup's (versions:
  libsoup 3.0 to 3.7.0) HTTP/2 connection tracking framework. When the library
  processes an HTTP/2 GOAWAY frame, it improperly handles the "Additional Debug
  Data"…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-125
vendor: Red Hat
product: libsoup3
affected:
  - libsoup3 (all versions)
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-07-14T19:15:34.225845Z'
exploitAvailable: true
published: '2026-07-14'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T17:54:16.248Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-15712'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-15712'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2499939'
    label: RHBZ#2499939
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/work_items/540'
tags:
  - cve.org
  - exploit-available
epss: 0.00629
epssPercentile: 0.50418
ingestedAt: '2026-11-06T18:00:12.494Z'
---

## Overview

A heap buffer over-read vulnerability was discovered in libsoup's (versions: libsoup 3.0 to 3.7.0) HTTP/2 connection tracking framework. When the library processes an HTTP/2 GOAWAY frame, it improperly handles the "Additional Debug Data" payload by assuming the data stream is a safely NUL-terminated C-string. Because the parser lacks strict length-boundary verification before reading this data, a remote, unauthenticated attacker can intentionally send a malformed GOAWAY frame missing the appropriate null delimiter. This causes the library to read past the end of the allocated buffer, triggering an application crash that results in a denial of service (DoS), or potentially exposing fragments of memory contents.

## Affected

- `libsoup3 (all versions)`

## Remediation

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

### Workarounds

The vulnerability requires debug logging to be enabled with the G_MESSAGES_DEBUG environment variable, e.g. G_MESSAGES_DEBUG=all or G_MESSAGES_DEBUG=libsoup-http2. Ensure this environment variable is not set.