Description
A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer overflow.
Published: 2026-09-29
Score: 8.6 High
EPSS: < 1% Very Low
KEV: No
AI Analysis

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Remediation

Vendor Workaround

To mitigate this enforce application-level limits on outgoing WebSocket message sizes. Do not send untrusted bulk data as a single WebSocket message.

Tracking

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Advisories

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History

Wed, 30 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 30 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Libsoup
Libsoup libsoup
Vendors & Products Libsoup
Libsoup libsoup

Tue, 29 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Description A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer overflow.
Title Libsoup: libsoup: heap buffer overflow during websocket client-frame masking
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-125
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H'}


Subscriptions

Libsoup Libsoup
Redhat Enterprise Linux
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-09-30T20:11:07.609Z

Reserved: 2026-09-29T13:19:23.247Z

Link: CVE-2026-102559

cve-icon Vulnrichment

Updated: 2026-09-30T19:42:44.706Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-29T18:17:08.503

Modified: 2026-09-30T21:17:04.667

Link: CVE-2026-102559

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-30T20:40:32Z

Weaknesses