🛡️ CVE-2026-12478 on Debian — libsoup3

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

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.

Distribution advisory

This page covers CVE-2026-12478 as tracked by Debian, for the package libsoup3. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability low.

Weakness class

DEBIAN-CVE-2026-12478 is classified as CWE-125: Out-of-bounds Read. The code reads past the limits of a buffer, exposing adjacent memory contents or crashing the process.

Affected software

DEBIAN-CVE-2026-12478 is recorded against 1 package.

libsoup3

Timeline and source

Published on 14 July 2026 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

Details

Severity Unknown

CVSS Score N/A

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

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2026-07-14

Updated 2026-08-11

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
libsoup3	—	—

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2026-12478

🔗 NVD 🔗 Mitre

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