CVE-2026-32738

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 78% 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, nvd
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

A fix is available — apply it.

libheif is a HEIF and AVIF file format decoder and encoder. In versions 1.21.2 and below, a crafted 792-byte HEIF sequence file with samples_per_chunk=0 in the stsc box causes an unsigned integer underflow in the Chunk constructor (m_last_sample = 0 + 0 - 1 = UINT32_MAX), mapping all samples to an empty chunk and resulting in a denial of service. When any sample is accessed, the library reads from index 0 of an empty std::vector, causing a guaranteed SEGV (null-page read). The file parses successfully without producing an error; the crash occurs on the first frame access. This issue has been fixed in version 1.22.0.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

May 19, 2026

Last Modified

July 24, 2026

Advisory Details (1)

Auto-updated May 20, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Heap OOB Read / SEGV Crash via Zero samples_per_chunk in stsc <=1.21.2 · Advisory · strukturag/libheif · GitHub

https://github.com/strukturag/libheif/security/advisories/GHSA-7f2h-cmpf-v9ww

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibheif1 (1.17.6-1ubuntu4.4) @ noble2026-07-26ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 9× in last 7d / 45× 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.

Showing the most recent 100 of 124 total refreshes for this CVE.

  1. 2026-07-30 16:28 UTCEPSS rescore
  2. 2026-07-30 01:30 UTCEPSS rescore
  3. 2026-07-27 14:13 UTCEPSS rescore
  4. 2026-07-26 14:54 UTCEPSS rescore
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 08:19 UTCEG score recompute
  7. 2026-07-26 08:19 UTCVendor advisory
  8. 2026-07-25 14:18 UTCEPSS rescore
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  14. 2026-07-23 03:09 UTCEG score recompute
  15. 2026-07-22 14:08 UTCEPSS rescore
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  24. 2026-07-18 10:04 UTCEPSS rescore
  25. 2026-07-17 23:29 UTCOSV refresh
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  1. 2026-07-16 17:03 UTCEPSS rescore
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  19. 2026-07-05 02:30 UTCEPSS rescore
  20. 2026-07-04 06:31 UTCEPSS rescore
  21. 2026-07-01 15:06 UTCEPSS rescore
  22. 2026-06-30 23:22 UTCEPSS rescore
  23. 2026-06-29 20:42 UTCVendor advisory
  24. 2026-06-29 14:06 UTCEPSS rescore
  25. 2026-06-29 14:06 UTCEPSS rescore
  26. 2026-06-28 14:07 UTCEPSS rescore
  27. 2026-06-28 14:07 UTCEPSS rescore
  28. 2026-06-28 04:56 UTCEPSS rescore
  29. 2026-06-28 04:56 UTCEPSS rescore
  30. 2026-06-27 20:23 UTCVendor advisory
  31. 2026-06-27 03:08 UTCEPSS rescore
  32. 2026-06-26 19:46 UTCVendor advisory
  33. 2026-06-25 16:48 UTCVendor advisory
  34. 2026-06-25 13:49 UTCEPSS rescore
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  36. 2026-06-24 14:05 UTCEPSS rescore
  37. 2026-06-23 21:33 UTCEPSS rescore
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  39. 2026-06-22 14:25 UTCEPSS rescore
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  41. 2026-06-21 14:56 UTCEPSS rescore
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  43. 2026-06-21 01:59 UTCEPSS rescore
  44. 2026-06-19 19:25 UTCEPSS rescore
  45. 2026-06-19 19:25 UTCEPSS rescore
  46. 2026-06-18 17:52 UTCEPSS rescore
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  48. 2026-06-17 17:53 UTCEPSS rescore
  49. 2026-06-16 17:52 UTCEPSS rescore
  50. 2026-06-15 17:49 UTCEPSS rescore
  51. 2026-06-14 23:18 UTCEPSS rescore
  52. 2026-06-13 23:00 UTCEPSS rescore
  53. 2026-06-12 23:12 UTCEPSS rescore
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  55. 2026-06-11 14:00 UTCEPSS rescore
  56. 2026-06-10 22:18 UTCEPSS rescore
  57. 2026-06-10 13:22 UTCEPSS rescore
  58. 2026-06-08 14:17 UTCEPSS rescore
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  60. 2026-06-07 15:25 UTCEPSS rescore
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  63. 2026-06-06 13:47 UTCEPSS rescore
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  72. 2026-06-01 13:52 UTCEPSS rescore
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  74. 2026-06-01 13:51 UTCEPSS rescore
  75. 2026-05-31 22:30 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-32738?
CVE-2026-32738 is a medium vulnerability published on May 19, 2026. libheif is a HEIF and AVIF file format decoder and encoder. In versions 1.21.2 and below, a crafted 792-byte HEIF sequence file with samplesperchunk=0 in the stsc box causes an unsigned integer underflow in the Chunk constructor (mlastsample = 0 + 0 - 1 = UINT32_MAX), mapping all samples to an…
When was CVE-2026-32738 disclosed?
CVE-2026-32738 was first published in the National Vulnerability Database on May 19, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-32738 actively exploited?
CVE-2026-32738 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 77.5% of all scored CVEs.
What is the CVSS score of CVE-2026-32738?
CVE-2026-32738 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-32738?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-32738, 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.

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