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: 0.2% (4th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
6.2EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.2Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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
6.2MEDIUMmedium confidence
EG Risk
44
EG Risk 44/100

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 (value × EchelonGraph’s weight)
Severity62% × 45%
The EG Score, 6.2 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
4th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 25, 2026

Last Modified

September 9, 2026

Advisory Details (1)

Auto-updated Aug 25, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

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 rangeFix by version rangeDependents
openexr3.1.13-1 ... 3.4.6+ds-4 (11 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
openexr3.1.13-2 ... 3.4.6+ds-4 (7 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
openexr3.1.13-2, 3.4.6+ds-1, 3.4.6+ds-2, 3.4.6+ds-3, 3.4.6+ds-4
  • every version up to 3.4.14-0.1: fixed in 3.4.14-0.1
—

Weakness Classification(3)

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

Data Freshness Timeline

(refreshed 16× in last 7d / 47× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-11 19:39 UTCEG score recompute
  2. 2026-10-11 16:54 UTCEG score recompute
  3. 2026-10-11 14:17 UTCEG score recompute
  4. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  6. 2026-10-10 12:26 UTCEG score recompute
  7. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  8. 2026-10-09 08:10 UTCEG score recompute
  9. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  10. 2026-10-08 06:21 UTCEG score recompute
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  12. 2026-10-07 04:30 UTCEG score recompute
  13. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  14. 2026-10-06 02:43 UTCEG score recompute
  15. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  16. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  17. 2026-10-03 16:29 UTCEG score recompute
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  19. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  20. 2026-10-02 11:03 UTCEG score recompute
  21. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  22. 2026-10-01 08:43 UTCEG score recompute
  23. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  24. 2026-09-30 06:56 UTCEG score recompute
  25. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.2% · 4th percentile
Show 52 more
  1. 2026-09-29 01:48 UTCEG score recompute
  2. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  3. 2026-09-28 00:01 UTCEG score recompute
  4. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  5. 2026-09-26 22:13 UTCEG score recompute
  6. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  7. 2026-09-25 00:24 UTCEG score recompute
  8. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  9. 2026-09-22 20:10 UTCEG score recompute
  10. 2026-09-20 16:34 UTCEG score recompute
  11. 2026-09-19 14:47 UTCEG score recompute
  12. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  13. 2026-09-18 13:00 UTCEG score recompute
  14. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  15. 2026-09-17 11:13 UTCEG score recompute
  16. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  17. 2026-09-15 06:15 UTCEG score recompute
  18. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  19. 2026-09-14 04:26 UTCEG score recompute
  20. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  21. 2026-09-13 02:39 UTCEG score recompute
  22. 2026-09-12 00:51 UTCEG score recompute
  23. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  24. 2026-09-10 23:04 UTCEG score recompute
  25. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  26. 2026-09-09 01:20 UTCEG score recompute
  27. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  28. 2026-09-06 14:55 UTCEG score recompute
  29. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  30. 2026-09-05 13:08 UTCEG score recompute
  31. 2026-09-04 11:20 UTCEG score recompute
  32. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  33. 2026-09-02 07:43 UTCEG score recompute
  34. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  35. 2026-09-01 05:55 UTCEG score recompute
  36. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  37. 2026-08-31 03:55 UTCEG score recompute
  38. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  39. 2026-08-30 02:07 UTCEG score recompute
  40. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  41. 2026-08-29 00:20 UTCEG score recompute
  42. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  43. 2026-08-27 18:12 UTCEG score recompute
  44. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  45. 2026-08-26 16:13 UTCEG score recompute
  46. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  47. 2026-08-25 14:21 UTCEG score recompute
  48. 2026-08-25 14:00 UTCEG score recompute
  49. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  50. 2026-08-25 01:19 UTCEG score recompute
  51. 2026-08-25 00:45 UTCEG score recomputeFirst assessed: 6.2 MEDIUM
  52. 2026-08-25 00:45 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-55373?
CVE-2026-55373 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-55373 published?
The CVE record for CVE-2026-55373 was published on August 25, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-55373 actively exploited?
CVE-2026-55373 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (4th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55373?
CVE-2026-55373 has a CVSS base score of 6.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55373?
A fix for CVE-2026-55373 is available: update to the fixed version the vendor names in its advisory.

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