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Fencer Vulns
medium 5.9

CVE-2026-34380 json

OpenEXR has a signed integer overflow (undefined behavior) in undo_pxr24_impl may allow bounds-check bypass in PXR24 decompression

published 2026-04-06 7 mo ago modified 2026-10-26 13 d ago also EUVD-2026-19307 , JLSEC-2026-144

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Patch / fix

  • julia OpenEXR_jll 3.4.9+0
  • openexr openexr 3.2.7, 3.3.9, 3.4.9
  • openexr Debian 14 3.4.14-0.1

debian advisories DEBIAN-CVE-2026-34380

  • openexr Ubuntu Pro 24.04 LTS 3.1.5-5.1ubuntu0.1~esm1
  • openexr Ubuntu Pro 26.04 LTS 3.1.13-2ubuntu0.26.04.1~esm1

ubuntu advisories UBUNTU-CVE-2026-34380

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openexr openSUSE Leap 16.0 3.2.2-160000.6.1
  • openexr openSUSE Tumbleweed 3.4.9-1.1

opensuse advisories openSUSE-SU-2026:20605-1openSUSE-SU-2026:10505-1

  • openexr Alpine 3.22 3.3.11-r0
  • openexr Alpine 3.23 3.4.13-r0
  • openexr Alpine 3.24 3.4.10-r0

alpine advisories ALPINE-CVE-2026-34380

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-34380 updated cvss 5.3

OpenEXR: OpenEXR: Denial of Service due to signed integer overflow in image decoding

  • Red Hat Enterprise Linux 6 OpenEXR, OpenEXR-libs Red Hat Enterprise Linux 7 OpenEXR, OpenEXR-libs
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 OpenEXR, OpenEXR-libs Red Hat Enterprise Linux 9 openexr, openexr-libs Red Hat Enterprise Linux 10 openexr
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-q3v8-hw4m-59w5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H

Affected packages

ecosystem package affected fixed in
julia OpenEXR_jll
>=3.1.4+0, <3.4.9+0
3.4.9+0

Affected products

  • AcademySoftwareFoundation openexr

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.