CVE-2026-55373

MEDIUMPre-NVD 6.26.2—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
6.2EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.2Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. Versions prior to 3.2.10, 3.3.12, and 3.4.13 contain an infinite-loop vulnerability in SampleCountChannel. The helper roundListSizeUp() rounds a sample-list size up to the next power of two using repeated unsigned left shifts, which terminates for normal values but fails for UINT_MAX: the sequence reaches 0x80000000, and the next left shift wraps the 32-bit value to 0. Because 0 remains less than UINT_MAX, the loop never progresses and never exits. The bug is reachable through public OpenEXRUtil APIs, either by editing the sample-count buffer through SampleCountChannel::Edit (whose destructor calls endEdit()) or by calling SampleCountChannel::set(x, y, UINT_MAX) on a valid pixel. This issue has been fixed in versions 3.2.10, 3.3.12, and 3.4.13.

CVSS v3
6.2
EG Score
6.2(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity62% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

August 25, 2026

Last Modified

September 9, 2026

Advisory Details (1)

Auto-updated Aug 25, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

OpenEXRUtil SampleCountChannel endEdit() can loop forever on UINT_MAX sample counts · Advisory · AcademySoftwareFoundation/openexr · GitHub

https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-mff9-68x3-h8rh

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
openexr3.1.13-1 ... 3.4.6+ds-4 (10 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
openexr3.1.13-2 ... 3.4.6+ds-4 (6 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
openexr3.1.13-2, 3.4.6+ds-1, 3.4.6+ds-2, 3.4.6+ds-3, 3.4.6+ds-43.4.14-0.1—

Weakness Classification(3)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 42× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 14:47 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 13:00 UTCEG score recompute
  4. 2026-09-17 19:31 UTCEPSS rescore
  5. 2026-09-17 11:13 UTCEG score recompute
  6. 2026-09-16 14:08 UTCEPSS rescore
  7. 2026-09-15 06:15 UTCEG score recompute
  8. 2026-09-15 03:11 UTCEPSS rescore
  9. 2026-09-14 04:26 UTCEG score recompute
  10. 2026-09-13 16:47 UTCEPSS rescore
  11. 2026-09-13 02:39 UTCEG score recompute
  12. 2026-09-12 00:51 UTCEG score recompute
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-10 23:04 UTCEG score recompute
  15. 2026-09-10 09:35 UTCEPSS rescore
  16. 2026-09-09 01:20 UTCEG score recompute
  17. 2026-09-08 22:01 UTCEPSS rescore
  18. 2026-09-06 14:55 UTCEG score recompute
  19. 2026-09-06 13:47 UTCEPSS rescore
  20. 2026-09-05 13:08 UTCEG score recompute
  21. 2026-09-04 11:20 UTCEG score recompute
  22. 2026-09-04 05:06 UTCEPSS rescore
  23. 2026-09-02 07:43 UTCEG score recompute
  24. 2026-09-01 13:54 UTCEPSS rescore
  25. 2026-09-01 05:55 UTCEG score recompute
Show 17 more
  1. 2026-09-01 04:40 UTCEPSS rescore
  2. 2026-08-31 03:55 UTCEG score recompute
  3. 2026-08-30 19:17 UTCEPSS rescore
  4. 2026-08-30 02:07 UTCEG score recompute
  5. 2026-08-30 01:22 UTCEPSS rescore
  6. 2026-08-29 00:20 UTCEG score recompute
  7. 2026-08-28 21:41 UTCEPSS rescore
  8. 2026-08-27 18:12 UTCEG score recompute
  9. 2026-08-27 14:25 UTCEPSS rescore
  10. 2026-08-26 16:13 UTCEG score recompute
  11. 2026-08-26 14:46 UTCEPSS rescore
  12. 2026-08-25 14:21 UTCEG score recompute
  13. 2026-08-25 14:00 UTCEG score recompute
  14. 2026-08-25 13:49 UTCEPSS rescore
  15. 2026-08-25 01:19 UTCEG score recompute
  16. 2026-08-25 00:45 UTCEG score recompute
  17. 2026-08-25 00:45 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55373?
CVE-2026-55373 is a medium vulnerability published on August 25, 2026. OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. Versions prior to 3.2.10, 3.3.12, and 3.4.13 contain an infinite-loop vulnerability in SampleCountChannel. The helper roundListSizeUp() rounds a sample-list size up to the…
When was CVE-2026-55373 disclosed?
CVE-2026-55373 was first published in the National Vulnerability Database on August 25, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55373 actively exploited?
CVE-2026-55373 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.6% of all scored CVEs.
What is the CVSS score of CVE-2026-55373?
CVE-2026-55373 has a CVSS v3 base score of 6.2 (NVD).
How do I remediate CVE-2026-55373?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55373, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55373

Explore →

Is Your Infrastructure Affected by CVE-2026-55373?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs