CVE-2026-12478

Libsoup: incomplete fix for cve-2026-0716: out-of-bounds read in libsoup websocket frame processing (unmasked path)

Published Jul 14, 2026 CVSS 3.1 · 4.8 Medium EPSS < 1% KEV · Not listed
Description
The fix for CVE-2026-0716 (commit 6ff7ef0, libsoup 3.6.6) placed the integer overflow guard inside the if (masked) block, leaving unmasked server-to-client frames unprotected. A malicious WebSocket server can send a crafted unmasked frame with a payload length near UINT64_MAX to trigger an OOB read in a libsoup-based client when max_incoming_payload_size is set to 0.

Remediation

Vendor Workaround

To mitigate this issue, applications utilizing libsoup's WebSocket support should ensure that the `max_incoming_payload_size` is explicitly set to a non-zero value. This prevents the library from processing WebSocket frames with an unset or zero maximum payload size, which can lead to out-of-bounds reads. Consult application-specific documentation for configuring libsoup parameters.

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8975-1 libsoup vulnerabilities
History
Type Values Removed Values Added
First Time appeared Libsoup
Libsoup libsoup
Red Hat
Red Hat enterprise Linux
Vendors & Products Libsoup
Libsoup libsoup
Red Hat
Red Hat enterprise Linux
Type Values Removed Values Added
First Time appeared Redhat rhel Els
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
cpe:/a:redhat:enterprise_linux:10
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description The fix for CVE-2026-0716 (commit 6ff7ef0, libsoup 3.6.6) placed the integer overflow guard inside the if (masked) block, leaving unmasked server-to-client frames unprotected. A malicious WebSocket server can send a crafted unmasked frame with a payload length near UINT64_MAX to trigger an OOB read in a libsoup-based client when max_incoming_payload_size is set to 0.
Title Libsoup: incomplete fix for cve-2026-0716: out-of-bounds read in libsoup websocket frame processing (unmasked path)
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-125
CPEs cpe:/o:redhat:enterprise_linux:10
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 5, 2026, 5:02 PM
Reserved
Jun 16, 2026, 9:25 PM
Status
Awaiting Analysis
Published
Jul 14, 2026, 10:16 AM
Modified
Nov 5, 2026, 5:18 PM