CVE-2026-34544Public exploit

Heap corruption via integer-overflowed B44 row pointer

Published Apr 1, 2026 · Updated Apr 1, 2026

Out-of-bounds write in OpenEXR 3.4.0 through 3.4.7 allows attackers to crash applications by supplying a crafted B44 or B44A EXR file. In uncompress_b44_impl(), signed int multiplication of y by channel width nx wraps row0 before its allocated scratch buffer, after which memcpy writes decoded blocks through invalid row pointers. Exploitation requires an application or user to decode the crafted file; an immediate crash is most likely, while adjacent heap corruption depends on memory layout.

CVSS severity8.4
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in OpenEXR 3.4.0 through 3.4.7 allows attackers to crash applications by supplying a crafted B44 or B44A EXR file. In uncompress_b44_impl(), signed int multiplication of y by channel width nx wraps row0 before its allocated scratch buffer, after which memcpy writes decoded blocks through invalid row pointers. Exploitation requires an application or user to decode the crafted file; an immediate crash is most likely, while adjacent heap corruption depends on memory layout.

The record

CVE
CVE-2026-34544
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Academy Software Foundation
Product
OpenEXR
Classifications
CWE-787, CWE-190, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 2026Record 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, < 3.4.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Academy Software Foundation · OpenEXRversion=>= 3.4.0, < 3.4.8

Published CVSS scores

7.3NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
8.4GitHub, Inc.CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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 exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-190Integer Overflow or Wraparound
T1204.002Malicious File

Public exploit references

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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