VDB-389899 · CVE-2026-59679 · Nessus 335961

X.Org libXfont2 Font Server Client encoding out-of-bounds

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.9	$0-$5k	0.00

Summaryinfo

A vulnerability classified as very critical has been found in X.Org libXfont2. This issue affects some unknown processing of the component Font Server Client. This manipulation of the argument encoding causes out-of-bounds. The identification of this vulnerability is CVE-2026-59679. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability classified as very critical was found in X.Org libXfont2 (version now known). Affected by this vulnerability is some unknown processing of the component Font Server Client. The manipulation of the argument encoding with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability.

This vulnerability is known as CVE-2026-59679. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/01/2026).

The vulnerability scanner Nessus provides a plugin with the ID 335961 (RHEL 9 : libXfont2 (RHSA-2026:55447)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (335961) and CERT Bund (WID-SEC-2026-2658). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

Amazon Linux 2
Red Hat Enterprise Linux
RESF Rocky Linux
SUSE Linux
SUSE openSUSE
Oracle Linux
Open Source X.Org X11

Productinfo

Vendor

X.Org

Name

libXfont2

License

open-source

Website

Vendor: https://www.x.org/

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.9

VulDB Base Score: 9.9
VulDB Temp Score: 9.9
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 335961
Nessus Name: RHEL 9 : libXfont2 (RHSA-2026:55447)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/13/2026 Advisory disclosed
08/13/2026 +0 days VulDB entry created
09/01/2026 +19 days VulDB entry last update

Sourcesinfo

Vendor: x.org

Status: Not defined

CVE: CVE-2026-59679 (🔒)
GCVE (CVE): GCVE-0-2026-59679
GCVE (VulDB): GCVE-100-389899
CERT Bund: WID-SEC-2026-2658 - X.Org X11 (libXfont2): Mehrere Schwachstellen ermöglichen Privilegieneskalation und Denial of Service

Entryinfo

Created: 08/13/2026 23:40
Updated: 09/01/2026 19:03
Changes: 08/13/2026 23:40 (48), 08/17/2026 21:34 (2), 09/01/2026 19:03 (7)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.