CVE-2026-34543Public exploitNetwork attack vector

Heap disclosure via unchecked PXR24 output size

Published Apr 1, 2026 · Updated Apr 1, 2026

Information disclosure in OpenEXR 3.4.0 through 3.4.7 allows remote attackers to expose heap data through crafted PXR24 EXR files. undo_pxr24_impl accepts short libdeflate output and reconstructs pixels to the header-derived expected size instead of the returned outSize, reading uninitialized scratch-buffer bytes. Default file decoding triggers the read without authentication or user interaction, and the leaked bytes enter the decoded pixel data.

CVSS severity8.7
High
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in OpenEXR 3.4.0 through 3.4.7 allows remote attackers to expose heap data through crafted PXR24 EXR files. undo_pxr24_impl accepts short libdeflate output and reconstructs pixels to the header-derived expected size instead of the returned outSize, reading uninitialized scratch-buffer bytes. Default file decoding triggers the read without authentication or user interaction, and the leaked bytes enter the decoded pixel data.

The record

CVE
CVE-2026-34543
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Academy Software Foundation
Product
OpenEXR
Classifications
CWE-908
Attack vector
network
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 vectornetwork
Required privilegesunauthenticated

What is affected?

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

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource

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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