Cyber Resilience

CVE-2026-26981

Openexr 3.3.0 – 3.3.7

Public PoC
Published
24 February 2026
Modified
25 February 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS Score 0.0052 42th percentile
Risk Priority 51 floored blend · peak EPSS

Summary

CVE-2026-26981 is a medium-severity Signed to Unsigned Conversion Error (CWE-195) vulnerability in Openexr Openexr. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 42th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In versions 3.3.0 through 3.3.6 and 3.4.0 through 3.4.4, a heap-buffer-overflow (OOB read) occurs in the `istream_nonparallel_read` function in…

more

`ImfContextInit.cpp` when parsing a malformed EXR file through a memory-mapped `IStream`. A signed integer subtraction produces a negative value that is implicitly converted to `size_t`, resulting in a massive length being passed to `memcpy`. Versions 3.3.7 and 3.4.5 contain a patch.

CWE(s)
CWE-195

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

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CVE-2025-48071Same product: Openexr Openexr
CVE-2025-12840Same product: Openexr Openexr
CVE-2025-64182Same product: Openexr Openexr
CVE-2025-12495Same product: Openexr Openexr
CVE-2026-45696Same product: Openexr Openexr
CVE-2025-48072Same product: Openexr Openexr
CVE-2026-34545Same product: Openexr Openexr
CVE-2026-42216Same product: Openexr Openexr

Affected Assets

openexr
openexr
3.3.0 — 3.3.7 · 3.4.0 — 3.4.5

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover conversion errors through static analysis, fuzzing, or targeted unit tests.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented development standards and tools can enforce coding rules that prohibit or safely wrap such casts.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles can mandate safe integer handling and strong typing to avoid unsafe signed-to-unsigned casts.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (static analysis, code review, safe-integer standards) directly prevent signed-to-unsigned conversion errors.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect conversion-related defects before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates practices that can catch signed-to-unsigned conversion errors during design and coding.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify safe integer handling and type-conversion rules.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles include data-type safety and overflow prevention.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prohibit unsafe signed-to-unsigned casts and require defensive checks.

References