CVE-2026-12478
Libsoup: incomplete fix for cve-2026-0716: out-of-bounds read in libsoup websocket frame processing (unmasked path)
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.
INFO
Published Date :
July 14, 2026, 10:16 a.m.
Last Modified :
Oct. 24, 2026, 9:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-12478
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update libsoup to version 3.6.6 or later.
- Apply the fix for CVE-2026-0716.
- Ensure all server-to-client frames are protected.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-12478.
| URL | Resource |
|---|---|
| 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 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-12478 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-12478
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-12478 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-12478 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Added Translation Title: Red Hat Enterprise Linux 10 de Red Hat, Description: La corrección para CVE-2026-0716 (commit 6ff7ef0, libsoup 3.6.6) colocó la protección contra desbordamiento de entero dentro del bloque if (masked), dejando desprotegidos los fotogramas sin máscara de servidor a cliente. Un servidor WebSocket malicioso puede enviar un fotograma sin máscara manipulado con una longitud de carga útil cercana a UINT64_MAX para activar una lectura fuera de límites en un cliente basado en libsoup cuando max_incoming_payload_size se establece en 0. -
CVE Modified by [email protected]
Sep. 16, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/12xxx/CVE-2026-12478.json">CVE-2026-12478</a> -
CVE Modified by [email protected]
Sep. 15, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/12xxx/CVE-2026-12478.json">CVE-2026-12478</a> Added Reference https://access.redhat.com/security/cve/CVE-2026-12478 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2489655 Added Reference https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/518 Removed Reference https://access.redhat.com/security/cve/cve-2026-0716 Removed Reference https://access.redhat.com/security/cve/CVE-2026-12478 Removed Reference https://bugzilla.redhat.com/show_bug.cgi?id=2489655 Removed Reference https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/518 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 15, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-12478', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-15T14:42:08.156943Z'} -
CVE Modified by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Changed Affected [{'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'packageName': 'libsoup3', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unknown'}] [{'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'packageName': 'libsoup3', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}] -
New CVE Received by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'packageName': 'libsoup3', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unknown'}] 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L Added CWE CWE-125 Added Reference https://access.redhat.com/security/cve/cve-2026-0716 Added Reference https://access.redhat.com/security/cve/CVE-2026-12478 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2489655 Added Reference https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/518