CVE-2026-34544 OpenEXR: integer overflow to OOB write in uncompress_b44_impl()
A crafted EXR file triggers an integer overflow leading to out-of-bounds writes, potentially causing crashes or code execution in applications using the library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-34544?
CVE-2026-34544 is a high-severity vulnerability in Openexr Openexr, published on 1 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From version 3.4.0 to before version 3.4.8, a crafted B44 or B44A EXR file can cause an out-of-bounds write in any application that decodes it via exr_decoding_run(). Consequences range from immediate crash (most likely) to corruption of adjacent heap allocations (layout-dependent). This issue has been patched in version 3.4.8.
Which versions are affected by CVE-2026-34544?
7 open source packages ship an affected version, including openexr. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
openexr PyPI | From 3.2.0 to 3.2.6 | None |
openexr PyPI | From 3.2.0 to 3.2.6 | None |
openexr PyPI | From 3.2.0 | 3.4.8 |
openexr PyPI | From 3.3.0 to 3.3.8 | None |
openexr PyPI | From 3.3.0 to 3.3.8 | None |
openexr PyPI | From 3.4.0 | 3.4.8 |
1 more packages
openexr PyPI | From 3.4.0 | 3.4.8 |
Products include Openexr Openexr.
How do I fix CVE-2026-34544?
Upgrade openexr to 3.4.8 or later.
Is CVE-2026-34544 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34544 exists.
Other vulnerabilities in Openexr Openexr
- CVE-2023-5841 OpenEXR Heap Overflow in Scanline Deep Data Parsing
- CVE-2026-41142 OpenEXR is Vulnerable to Integer overflow in ImageChannel::resize leads to heap OOB write via OpenEXRUtil public API
- CVE-2026-42216 OpenEXR: Out-of-bounds read in `IDManifest::init()` during prefix expansion
- CVE-2017-9111 OpenEXR invalid write
- CVE-2017-9113 Memory corruption in n/a
Sources
Also known as BELL-CVE-2026-34544, CLSA-2026-1781180341, CLSA-2026-1781184685, DEBIAN-CVE-2026-34544, GHSA-h762-rhv3-h25v, JLSEC-2026-146 and 5 more.