OpenEXR: Integer overflow in the HTJ2K decoder leads to heap-buffer-overflow (CVE-2026-44663) | HOL Guard CVE

Medium · CVSS 6.1CVE-2026-44663

OpenEXR: Integer overflow in the HTJ2K decoder leads to heap-buffer-overflow

Answer in brief

CVE-2026-44663 records a Medium severity (CVSS 6.1) vulnerability in OpenEXR: Integer overflow in the HTJ2K decoder leads to heap-buffer-overflow. The current sources do not mark it as known exploited. The current feed maps AcademySoftwareFoundation/openexr (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jun 18, 2026Updated Jun 26, 2026Source checked Sep 19, 2026First seen by HOL Jun 22, 2026Material review Jun 26, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 6.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps AcademySoftwareFoundation/openexr (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
AcademySoftwareFoundation/openexrgeneric	>= 3.4.0, < 3.4.11	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for AcademySoftwareFoundation/openexr.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Jun 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jun 22, 2026

Sources and claim methodology

Upstream source description

OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. In versions 3.4.0 through 3.4.11, an integer overflow in ht_undo_impl() in src/lib/OpenEXRCore/internal_ht.cpp leads to a heap-buffer overflow when decoding a crafted HTJ2K-compressed EXR file. decode->channels[i].width (int32_t) is multiplied by bytes_per_element in 32-bit signed arithmetic. With large widths (e.g., >= 536870912 for FLOAT data), this overflows, producing a corrupted offset that is later used for pointer arithmetic and can cause a heap out-of-bounds write. The same unchecked multiplication pattern appears in two other HTJ2K paths (bytes-per-line accumulation and pixel-line pointer advancement). As with related CVE-2026-34378 through CVE-2026-34589 fixes in other codecs, validating only after the multiplication is too late because the value may already be overflowed. This issue has been fixed in version 3.4.12.

Quoted source text, attributed separately from HOL analysis.