VulnerabilityPublished 6 Apr 2026Updated 15 Jul 2026

CVE-2026-34379: AcademySoftwareFoundation openexr · Incorrect Type Conversion or Cast

Affects AcademySoftwareFoundation openexrSource CVE Database V5

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Not known to be exploited · CVSS 7.1 High · fixed in 3.4.9 : patch AcademySoftwareFoundation openexr soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

7.1High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.4.9, 3.3.9, 3.2.7

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 6 Apr 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 30 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 openexr and academysoftwarefoundation/openexr to 3.4.9, 3.3.9 or 3.2.7.

Affected software

Product	Affected	Fixed in
AcademySoftwareFoundationopenexr	Affected >=3.4.0 <3.4.9	Fixed in 3.4.9
AcademySoftwareFoundationopenexr	Affected >=3.3.0 <3.3.9	Fixed in 3.3.9
AcademySoftwareFoundationopenexr	Affected >=3.2.0 <3.2.7	Fixed in 3.2.7
GitHubacademysoftwarefoundation/openexr`pkg:github/academysoftwarefoundation/openexr`Other threats	Affected <3.2.7 <3.3.9 <3.4.9	Fixed in 3.2.7 3.3.9 3.4.9

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

AI-suggested

Fixed versions 3.2.7, 3.3.9, and 3.4.9 of openexr address this vulnerability. Users should upgrade to one of these versions to remediate the issue. No vendor advisory indicates alternative mitigations or that no action is required. Patch status is confirmed by the vendor advisory. No cloud service remediation applies as this is a library.

Description

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Impact

This vulnerability can cause application crashes (denial of service) on architectures enforcing strict memory alignment (e.g., ARM, RISC-V) when processing crafted EXR files. On x86 architectures, it may lead to undefined behavior exploitable via compiler optimizations, potentially impacting application stability or security. There is no direct evidence of confidentiality or integrity compromise, but availability is affected due to crashes.

Summary

OpenEXR versions prior to 3.2.7, 3.3.9, and 3.4.9 contain a vulnerability in LossyDctDecoder_execute() where an unaligned memory write occurs during HALF to FLOAT conversion of DWA/DWAB-compressed EXR files. The decoder casts an unaligned uint8_t * row pointer to float * and writes through it, causing undefined behavior and potential crashes on architectures like ARM and RISC-V that enforce alignment. On x86, this is tolerated at runtime but can be exploited due to compiler assumptions about alignment. This vulnerability is addressed by fixes in versions 3.2.7, 3.3.9, and 3.4.9.

CWE-704Incorrect Type Conversion or Cast (opens in a new tab)
Class weakness
The product does not correctly convert an object, resource, or structure from one type to a different type.
CWE-787Out-of-bounds Write (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #5
The product writes data past the end, or before the beginning, of the intended buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-843Access of Resource Using Incompatible Type (Type Confusion) (opens in a new tab)
Base weakness
The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.
CWE-475Undefined Behavior for Input to API (opens in a new tab)
Base weakness
The behavior of this function is undefined unless its control parameter is set to a specific value.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Jul 2026, 09:02 UTC

WeaknessesCWE-704, CWE-787, CWE-843 +1

Technical details

References

Community reviews

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