CVE-2026-12478

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

CVSS 4.8 MEDIUMCWE-125

Vexday Risk Score

10Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 4.8EPSS —KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

14 Jul 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

Affected products

Red Hat · Red Hat Enterprise Linux 10

References

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