EulerOS 2.0 SP12 : libXfont2 (EulerOS-SA-2026-4412)

critical Nessus Plugin ID 376786

Synopsis

The remote EulerOS host is missing multiple security updates.

Description

According to the versions of the libXfont2 packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) indexes the per-character encoding[] array using num_chars from the FS_QueryXBitmaps16 reply, but that array was allocated with a size derived from num_extents in the separate FS_QueryXExtents16 reply. The two CARD32 fields are never cross-checked.
A malicious or compromised font server can send a small num_extents (e.g. 1) in the extents reply, then a large num_chars (e.g. 100000) in the bitmaps reply. This causes attacker-controlled out-of-bounds heap read and writes.(CVE-2026-59679)

fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. It does not check whether the running destination cursor has exceeded the allocation.

A malicious font server can send overlapping source offsets -- for example 1000 glyphs each referencing {position:0, length:64} with nbytes=64. Each individual source range passes the existing validation, but the cumulative writes total 64000 bytes into a 64-byte destination buffer. This is a heap buffer overflow with attacker-controlled content.(CVE-2026-44950)

Tenable has extracted the preceding description block directly from the EulerOS libXfont2 security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected libXfont2 packages.

Plugin Details

Severity: Critical

ID: 376786

File Name: EulerOS_SA-2026-4412.nasl

Version: 1.1

Type: Local

Family: Huawei Local Security Checks

Published: 11/6/2026

Updated: 11/6/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.41

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 5.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-59679

CVSS v3

Risk Factor: Critical

Base Score: 9

Temporal Score: 7.8

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Critical

Base Score: 9.5

Threat Score: 8.4

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS Score Source: CVE-2026-44950

Vulnerability Information

CPE: cpe:/o:huawei:euleros:2.0, p-cpe:/a:huawei:euleros:libxfont2-help, p-cpe:/a:huawei:euleros:libxfont2

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/EulerOS/release, Host/EulerOS/rpm-list, Host/EulerOS/sp

Excluded KB Items: Host/EulerOS/uvp_version

Exploit Ease: No known exploits are available

Patch Publication Date: 11/5/2026

Vulnerability Publication Date: 8/5/2026

Reference Information

CVE: CVE-2026-44950, CVE-2026-59679

Detections

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