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Linux Distros Unpatched Vulnerability : CVE-2026-39886

medium Nessus Plugin ID 309639

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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.

 - OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. Versions 3.4.0 through 3.4.9 have a signed integer overflow vulnerability in OpenEXR's HTJ2K (High-Throughput JPEG 2000) decompression path. The `ht_undo_impl()` function in `src/lib/OpenEXRCore/internal_ht.cpp` accumulates a bytes-per-line value (`bpl`) using a 32-bit signed integer with no overflow guard. A crafted EXR file with 16,385 FLOAT channels at the HTJ2K maximum width of 32,767 causes `bpl` to overflow `INT_MAX`, producing undefined behavior confirmed by UBSan. On an allocator-permissive host where the required ~64 GB allocation succeeds, the wrapped negative `bpl` value would subsequently be used as a per-scanline pointer advance, which would produce a heap out- of-bounds write. On a memory-constrained host, the allocation fails before `ht_undo_impl()` is entered.
 This is the second distinct integer overflow in `ht_undo_impl()`. CVE-2026-34545 addressed a different overflow in the same function the `int16_t p` pixel-loop counter at line ~302 that overflows when iterating over channels whose `width` exceeds 32,767. The CVE-2026-34545 fix did not touch the `int bpl` accumulator at line 211, which is the subject of this advisory. The `bpl` accumulator was also not addressed by any of the 8 advisories in the 2026-04-05 v3.4.9 release batch. This finding is structurally identical to CVE-2026-34588 (PIZ `wcount*nx` overflow in `internal_piz.c`) and should be remediated with the same pattern. The CVE-2026-34588 fix did not touch `internal_ht.cpp`. Version 3.4.10 contains a remediation that addresses the vulnerability in `internal_ht.cpp`. (CVE-2026-39886)

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://access.redhat.com/security/cve/cve-2026-39886

https://security-tracker.debian.org/tracker/CVE-2026-39886

Plugin Details

Severity: Medium

ID: 309639

File Name: unpatched_CVE_2026_39886.nasl

Version: 1.3

Type: Local

Agent: unix

Family: Misc.

Published: 4/22/2026

Updated: 4/23/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 2.9

CVSS v2

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.9

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

CVSS Score Source: CVE-2026-39886

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 5

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

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

Vulnerability Information

CPE: cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:9, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:6, p-cpe:/a:centos:centos:openexr, p-cpe:/a:redhat:enterprise_linux:openexr-devel, p-cpe:/a:debian:debian_linux:openexr, cpe:/o:centos:centos:8, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:centos:centos:openexr-libs, p-cpe:/a:centos:centos:openexr-devel, p-cpe:/a:redhat:enterprise_linux:openexr-libs, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:redhat:enterprise_linux:openexr

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

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 4/19/2026

Reference Information

CVE: CVE-2026-39886