CVE-2026-12478

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.

• How can I get the fixes?
• What do statuses mean?
• Patch details

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Patch details

Severity score breakdown

CVSS version: CVSS v3.0

References

• MITRE
• NVD
• Launchpad
• Debian

Related Ubuntu Security Notices (USN)

• USN-8975-1
• libsoup vulnerabilities
• 3 November 2026

Other references

• https://www.cve.org/CVERecord?id=CVE-2026-12478
• https://access.redhat.com/security/cve/CVE-2026-12478
• https://access.redhat.com/security/cve/cve-2026-0716
• https://bugzilla.redhat.com/show_bug.cgi?id=2489655
• https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/518