CVE-2025-12840

Code execution via unchecked EXR copy length

Published Dec 23, 2025 · Updated Dec 23, 2025

Heap-based buffer overflow in OpenEXR 3.4.0 allows remote attackers to execute code after a user opens a crafted EXR file. The EXR parser accepts a user-controlled length without validating it against the destination allocation before copying data into a heap buffer. Exploitation requires user interaction and runs attacker code in the context of the process that parses the file.

CVSS severity7.8
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in OpenEXR 3.4.0 allows remote attackers to execute code after a user opens a crafted EXR file. The EXR parser accepts a user-controlled length without validating it against the destination allocation before copying data into a heap buffer. Exploitation requires user interaction and runs attacker code in the context of the process that parses the file.

The record

CVE
CVE-2025-12840
Published
Dec 23, 2025
Updated
Dec 23, 2025
Vendor
Academy Software Foundation
Product
OpenEXR
Classifications
CWE-122, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.4.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Academy Software Foundation · OpenEXRversion=3.4.0

Published CVSS scores

7.8Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1204.002Malicious File
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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