CVE-2026-59956

MEDIUMPre-NVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 94% 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
Trending — 3 sources updated this weekElevated
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: Elevated riskExposed: 0

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

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1, An uncompressed 16-bit iff image with a z-buffer makes iffinput::readimg() allocate a temporary scanline from m_header.rgba_count but copy from it using m_header.pixel_bytes(), whose stride also includes z-buffer bytes. the oversized memcpy reads beyond the temporary heap buffer and copies adjacent memory into the output image, resulting in a crash or disclosure of adjacent heap data. The affected implementation is identified by src/iff.imageio/iffinput.cpp, IffInput::readimg(), m_header.rgba_count, and m_header.pixel_bytes(), which define the relevant source path, functions, state, and trigger. This issue is fixed in versions 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1.

CVSS v3
6.1
EG Score
6.1(medium)
EG Risk
43(Track)
EG Risk 43/100SSVC: 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
Severity61% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
6%
KEV
Not listed

Published

September 18, 2026

Last Modified

September 24, 2026

Advisory Details (5)

Auto-updated Sep 18, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

v3.1.15.0

Patch available: AcademySoftwareFoundation/OpenImageIO v3.1.15.0

https://github.com/AcademySoftwareFoundation/OpenImageIO/releases/tag/v3.1.15.0
github_release Patch Available

v3.0.20.0

Patch available: AcademySoftwareFoundation/OpenImageIO v3.0.20.0

https://github.com/AcademySoftwareFoundation/OpenImageIO/releases/tag/v3.0.20.0
github_commit

commit f01bd16764b2 (AcademySoftwareFoundation/OpenImageIO)

Fix landed in AcademySoftwareFoundation/OpenImageIO commit f01bd16764b2 — awaiting tagged release

https://github.com/AcademySoftwareFoundation/OpenImageIO/commit/f01bd16764b2a06f372899e3e302280a7f9c8c02
github_pr

fix(iff): Fix allocation bug when reading 16 bit RGBA + float z

Fix merged in AcademySoftwareFoundation/OpenImageIO PR #5251 on 2026-06-27 — awaiting tagged release

https://github.com/AcademySoftwareFoundation/OpenImageIO/pull/5251
github Patch Available🟡 PoC Available

Heap-buffer-overread in IffInput::readimg() when ZBUFFER flag is set · Advisory · AcademySoftwareFoundation/OpenImageIO · GitHub

https://github.com/AcademySoftwareFoundation/OpenImageIO/security/advisories/GHSA-hjfv-gvxc-qgvh

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 13× 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. 2026-09-24 21:39 UTCEG score recompute
  2. 2026-09-24 14:04 UTCEPSS rescore
  3. 2026-09-23 21:37 UTCEG score recompute
  4. 2026-09-23 17:54 UTCEPSS rescore
  5. 2026-09-22 21:02 UTCEG score recompute
  6. 2026-09-21 20:26 UTCEG score recompute
  7. 2026-09-20 20:16 UTCEPSS rescore
  8. 2026-09-19 19:07 UTCEG score recompute
  9. 2026-09-18 18:28 UTCEG score recompute
  10. 2026-09-18 17:49 UTCEG score recompute
  11. 2026-09-18 16:26 UTCEG score recompute
  12. 2026-09-18 15:47 UTCEG score recompute
  13. 2026-09-18 15:44 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-59956?
CVE-2026-59956 is a medium vulnerability published on September 18, 2026. OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1, An uncompressed 16-bit iff image with a z-buffer makes iffinput::readimg() allocate a temporary scanline from…
When was CVE-2026-59956 disclosed?
CVE-2026-59956 was first published in the National Vulnerability Database on September 18, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59956 actively exploited?
CVE-2026-59956 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 94.4% of all scored CVEs.
What is the CVSS score of CVE-2026-59956?
CVE-2026-59956 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-59956?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59956, 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

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