CVE-2026-34379
OpenEXR has a misaligned write in LossyDctDecoder_execute leading to undefined behavior (DWA/DWAB decompression)
Description
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 misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.
INFO
Published Date :
April 6, 2026, 4:16 p.m.
Last Modified :
April 7, 2026, 7:04 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE |
Solution
- Update to OpenEXR version 3.2.7 or later.
- Update to OpenEXR version 3.3.9 or later.
- Update to OpenEXR version 3.4.9 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-34379.
| URL | Resource |
|---|---|
| https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7 | Product Release Notes |
| https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9 | Product Release Notes |
| https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9 | Product Release Notes |
| https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-w88v-vqhq-5p24 | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-34379 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-34379
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-34379 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-34379 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 07, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:* versions from (including) 3.2.0 up to (excluding) 3.2.7 *cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:* versions from (including) 3.3.0 up to (excluding) 3.3.9 *cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:* versions from (including) 3.4.0 up to (excluding) 3.4.9 Added Reference Type GitHub, Inc.: https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-w88v-vqhq-5p24 Types: Exploit, Vendor Advisory -
CVE Modified by [email protected]
Apr. 07, 2026
Action Type Old Value New Value Added Reference https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7 Added Reference https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9 Added Reference https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9 -
New CVE Received by [email protected]
Apr. 06, 2026
Action Type Old Value New Value Added Description 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 misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H Added CWE CWE-787 Added CWE CWE-704 Added CWE CWE-843 Added Reference https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-w88v-vqhq-5p24