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Linux Distros Unpatched Vulnerability : CVE-2026-54240

critical Nessus Plugin ID 324486

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

 - decoder_context::decode_slice_unit_tiles (libde265/decctx.cc:920) reads pps.CtbAddrRStoTS[ctbAddrRS] at line 966 where ctbAddrRS = ctbY * ctbsWidth + ctbX is computed from PPS-supplied colBd[]/rowBd[] arrays without validating the result against CtbAddrRStoTS.size() == sps->PicSizeInCtbsY. A malformed PPS that passes set_derived_values but encodes geometry inconsistent with the SPS produces a ctbAddrRS past the allocation, causing a 4-byte heap-buffer-overflow READ. (CVE-2026-45382) A heap buffer overflow (out-of- bounds READ) exists in decoder_context::decode_slice_unit_WPP() in libde265/decctx.cc. When decoding a WPP (Wavefront Parallel Processing) HEVC slice, ctbAddrRS is computed as ctbRow * ctbsWidth inside the entry- point loop. If the PPS/SPS headers are crafted so that this value exceeds pps.CtbAddrRStoTS.size(), the subsequent array access pps.CtbAddrRStoTS[ctbAddrRS] reads past the end of the allocated vector, triggering a heap-buffer-overflow confirmed by AddressSanitizer. (CVE-2026-45383) Pixel accessor signed integer overflow causes heap OOB read/write (CVE-2026-54240) SAO sequential filter heap buffer overflow via signed integer overflow (CVE-2026-54241) (CVE-2026-54240)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://security-tracker.debian.org/tracker/CVE-2026-54240

https://ubuntu.com/security/CVE-2026-54240

Plugin Details

Severity: Critical

ID: 324486

File Name: unpatched_CVE_2026_54240.nasl

Version: 1.6

Type: Local

Agent: unix

Family: Misc.

Published: 7/1/2026

Updated: 9/2/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.12

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.4

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

CVSS Score Source: CVE-2026-54240

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:canonical:ubuntu_linux:libde265, p-cpe:/a:debian:debian_linux:libde265

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Reference Information

CVE: CVE-2026-54240