VulnerabilityPublished 24 Feb 2026

CVE-2026-26981: AcademySoftwareFoundation openexr · Signed to Unsigned Conversion Error

Affects AcademySoftwareFoundation openexrSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 3.4.5 or 3.3.7 when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.4.5, 3.3.7

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade AcademySoftwareFoundation openexr to 3.4.5 or 3.3.7.

Affected software

Product	Affected	Fixed in
AcademySoftwareFoundationopenexr	Affected >=3.4.0 <3.4.5	Fixed in 3.4.5
AcademySoftwareFoundationopenexr	Affected >=3.3.0 <3.3.7	Fixed in 3.3.7
GitHubacademysoftwarefoundation/openexr`pkg:github/academysoftwarefoundation/openexr`Other threats	Affected =3.3.0 <=3.3.6 >=3.4.0 <=3.4.4	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade openexr to versions 3.3.7 or 3.4.5 or later, where the vulnerability is patched.
Implement strict validation and sanitization of EXR files before processing, especially from untrusted sources.
Employ sandboxing or containerization for applications that parse EXR files to contain potential crashes or memory corruption.
Monitor application logs and crash reports for anomalies related to EXR file processing.
Restrict network exposure of services that automatically ingest EXR files to trusted sources only.
Educate users and operators about the risks of opening untrusted EXR files and enforce policies to avoid processing files from unknown origins.
Consider runtime memory protection mechanisms such as ASLR and DEP to mitigate exploitation impact.
Conduct regular vulnerability scanning and patch management to ensure timely updates.

Description

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 `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.

Impact

This vulnerability can cause denial of service by crashing applications that parse EXR files using vulnerable openexr versions. In environments where openexr is integrated into media production pipelines, automated image processing, or rendering workflows, an attacker could disrupt operations by supplying malformed EXR files. While no direct confidentiality or integrity compromise is indicated, the availability impact could delay production schedules and cause operational downtime. Since exploitation requires user interaction (opening or processing a crafted file), the risk is mitigated somewhat but remains significant in environments processing untrusted EXR files. The lack of privilege requirements and network attack vector means attackers can remotely trigger the issue if file ingestion is exposed. Organizations relying on openexr for critical imaging tasks should consider this a medium risk that could affect service continuity.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Mar 2026, 01:56 UTC

WeaknessesCWE-195

Technical details

References

Community reviews

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