CVE-2026-55373Public exploit

Process hang via wrapped sample-list sizing loop

Published Aug 25, 2026 · Updated Aug 25, 2026

Infinite loop in OpenEXRUtil in Academy Software Foundation OpenEXR allows local users to hang a process with UINT_MAX sample counts. The roundListSizeUp() helper repeatedly left-shifts an unsigned 32-bit allocation size; UINT_MAX wraps the counter to zero, so SampleCountChannel::endEdit() and set() never exit. Reachability requires application code to pass the extreme count through the public C++ API; no crafted-file or native network path was demonstrated.

CVSS severity6.2
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite loop in OpenEXRUtil in Academy Software Foundation OpenEXR allows local users to hang a process with UINT_MAX sample counts. The roundListSizeUp() helper repeatedly left-shifts an unsigned 32-bit allocation size; UINT_MAX wraps the counter to zero, so SampleCountChannel::endEdit() and set() never exit. Reachability requires application code to pass the extreme count through the public C++ API; no crafted-file or native network path was demonstrated.

The record

CVE
CVE-2026-55373
Published
Aug 25, 2026
Updated
Aug 25, 2026
Vendor
Academy Software Foundation
Product
OpenEXR
Classifications
CWE-835, CWE-190, CWE-400, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=< 3.2.10
  2. Affected versionversion=>= 3.3.0, < 3.3.12
  3. Affected versionversion=>= 3.4.0, < 3.4.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Academy Software Foundation · OpenEXRversion=< 3.2.10; version=>= 3.3.0, < 3.3.12; version=>= 3.4.0, < 3.4.13

Published CVSS scores

6.2GitHub_MCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
CWE-190Integer Overflow or Wraparound
CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

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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