FreeBSD : Emacs -- Heap out-of-bounds write when rendering SVG images (c7be43b0-78f0-11f1-8898-1c697a616631)

high Nessus Plugin ID 325258

Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the c7be43b0-78f0-11f1-8898-1c697a616631 advisory.

When GNU Emacs renders an SVG image whose image spec includes a :css property, an off-by-one error in svg_load_image() writes a NUL byte one position past the end of a heap allocation. The copied string is also left without NUL termination within its allocation, causing a subsequent out-of-bounds read.
A single NUL byte heap overflow is a well-understood exploitation primitive (poison NUL byte) that can corrupt heap metadata and potentially be escalated to arbitrary code execution. The overflow can be triggered by Lisp code that displays an SVG image with a crafted :css property.

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

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

Solution

Update the affected packages.

Plugin Details

Severity: High

ID: 325258

File Name: freebsd_pkg_c7be43b078f011f188981c697a616631.nasl

Version: 1.1

Type: Local

Family: FreeBSD Local Security Checks

Published: 7/6/2026

Updated: 7/6/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.64

CVSS v2

Risk Factor: Medium

Base Score: 6.6

Temporal Score: 4.9

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

CVSS Score Source: CVE-2026-6861

CVSS v3

Risk Factor: High

Base Score: 7.1

Temporal Score: 6.2

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

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

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:emacs-devel-nox, p-cpe:/a:freebsd:freebsd:emacs-wayland, p-cpe:/a:freebsd:freebsd:emacs-nox, p-cpe:/a:freebsd:freebsd:emacs-canna, p-cpe:/a:freebsd:freebsd:emacs, cpe:/o:freebsd:freebsd, p-cpe:/a:freebsd:freebsd:emacs-devel

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 7/6/2026

Vulnerability Publication Date: 4/14/2026

Reference Information

CVE: CVE-2026-6861

Detections

Analytics