CVE Intelligence
High Memory corruption exploit reference

CVE-2026-34543 — OpenEXR: Heap information disclosure in PXR24 decompression via unchecked decompressed size (undo_pxr24_impl)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From version 3.4.0 to before version 3.4.8, sensitive information from heap memory may be leaked through the decoded pixel data (information disclosure). This occurs under default settings; simply reading a malicious EXR file is sufficient to trigger the issue, without any user interaction. This issue has been patched in version 3.4.8.

Published Apr 1, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.5% (30-day exploitation probability)+6
  • Technical severity (high)+6
  • CISA SSVC: exploitation "poc"+5
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.52%
ahead of 43% of scored CVEs · Oct 14, 2026
Affects
AcademySoftwareFoundation
Openexr
CVSS base
7.5
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (AcademySoftwareFoundation Openexr, Openexr Openexr).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
AcademySoftwareFoundation Openexr version >= 3.4.0, < 3.4.8 Vulnerable CVE Program (cve.org) e CISA ADP
Openexr Openexr ≥ 3.2.0 and < 3.2.7≥ 3.3.0 and < 3.3.9≥ 3.4.0 and < 3.4.8 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.7 CVSS 4.0 High — — security-advisories@github.com via NIST National Vulnerability Database
8.7 CVSS 4.0 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
7.5 CVSS 3.1 High 3.9 3.6 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-908 · Use of Uninitialized Resource

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.52%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · academysoftwarefoundation/openexr
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 7.5
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Apr 1, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

3 on the record

Elsewhere on this site

AcademySoftwareFoundation
every CVE for this vendor
Memory corruption
same class
CWE-908
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-68515 OpenEXR: Heap out-of-bounds write in exrmultiview with subsampled channel union Aug 25, 2026
  • CVE-2026-68513 OpenEXR: Heap buffer overflow in PyOpenEXR from literal/prefixed RGB channel name collision Aug 25, 2026
  • CVE-2026-68514 OpenEXR: Heap buffer overflow in PyOpenEXR from literal/prefixed RGB channel name collision in deep images Aug 25, 2026
  • CVE-2026-59981 OpenEXR: Heap OOB read in SampleCountChannel row when using nonzero dataWindow Aug 25, 2026
  • CVE-2026-62986 OpenEXR: PyOpenEXR deep prefixed RGB stale lane disclosure Aug 25, 2026
  • CVE-2026-65979 OpenEXR: Out-of-bounds read in HTJ2K decoder from unvalidated chunk header length (PLEN) Aug 25, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-34543 is "OpenEXR: Heap information disclosure in PXR24 decompression via unchecked decompressed size (undo_pxr24_impl)", rated High. It affects Openexr (AcademySoftwareFoundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.52% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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