---
id: CVE-2026-102560
title: A flaw was found in libsoup
summary: >-
  A flaw was found in libsoup. When the permessage-deflate WebSocket extension
  compresses a very large outgoing message, truncated size calculations used for
  GByteArray growth could wrap, causing zlib to write past the allocated buffer
  and…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H'
cwe:
  - CWE-125
vendor: Red Hat
product: libsoup3
affected:
  - libsoup3 (all versions)
  - libsoup (all versions)
  - libsoup
  - libsoup (all versions)
  - libsoup (all versions)
published: '2026-09-29'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T17:17:09.807'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102560'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:83384'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:83618'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-102560'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2543296'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-102560.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-102560'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102560'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-29T19:51:42.455534Z'
epss: 0.00521
epssPercentile: 0.44351
ingestedAt: '2026-09-29T17:41:02.260Z'
---

## Overview

A flaw was found in libsoup. When the permessage-deflate WebSocket extension compresses a very large outgoing message, truncated size calculations used for GByteArray growth could wrap, causing zlib to write past the allocated buffer and resulting in a heap buffer overflow.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-29 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-102560.json)