CVE-2026-12478

Public on 2026-07-14

Modified on 2026-07-15

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.

Severity

Medium

See what this means

CVSS v3 Base Score

4.8

See breakdown

Affected Packages

Platform	Package	Status
Amazon Linux 2 - Core	libsoup	Pending Fix
Amazon Linux 2023	libsoup	Pending Fix
Amazon Linux 2023	libsoup3	Pending Fix

CVSS Scores

	Score Type	Score	Vector
Amazon Linux	CVSSv3	4.8	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

References

FAQs regarding Amazon Linux ALAS/CVE Severity Red Hat: CVE-2026-12478 Mitre: CVE-2026-12478