CVE-2026-34588
Because nx, ny, and wcount are int, a crafted EXR file can make this product overflow and wrap.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.48%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.1.0 to before 3.2.7, 3.3.9, and 3.4.9, internal_exr_undo_piz() advances the working wavelet pointer with signed 32-bit arithmetic. Because nx, ny, and wcount are int, a crafted EXR file can make this product overflow and wrap. The next channel then decodes from an incorrect address. The wavelet decode path operates in place, so this yields both out-of-bounds reads and out-of-bounds writes. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.
- CVSS 4.0
- 8.6 HIGHCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.48% probability · 40th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-125, CWE-190, CWE-787
- Affected
- openexr/openexr
- Source
- security-advisories@github.com
References
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7Product, Release Notes
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9Product, Release Notes
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9Product, Release Notes
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-588r-cr5c-w6hfExploit, Mitigation, Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:15887
- https://access.redhat.com/errata/RHSA-2026:15888
- https://access.redhat.com/errata/RHSA-2026:17656
- https://access.redhat.com/errata/RHSA-2026:17658
- https://access.redhat.com/errata/RHSA-2026:17659
- https://access.redhat.com/errata/RHSA-2026:17660
- https://access.redhat.com/errata/RHSA-2026:19146
- https://access.redhat.com/errata/RHSA-2026:19359
- https://access.redhat.com/errata/RHSA-2026:19587
- https://access.redhat.com/errata/RHSA-2026:30078
- https://access.redhat.com/errata/RHSA-2026:30087
- https://access.redhat.com/errata/RHSA-2026:30088
- https://access.redhat.com/errata/RHSA-2026:30089
- https://access.redhat.com/security/cve/CVE-2026-34588
- https://bugzilla.redhat.com/show_bug.cgi?id=2455408
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34588.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.