CVE-2026-62291

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 97% 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
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: Elevated riskExposed: 0

A fix is available — apply it.

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted image sequence with a 2x2 primary plane and a 256x256 auxiliary alpha plane can cause attacker-controlled heap corruption during a normal decode and re-encode workflow. Track_Visual::decode_next_image_sample() calls transfer_channel_from_image_as() without checking that the auxiliary alpha dimensions match the main frame. The resulting inconsistent image reaches heif_track_decode_next_image() and then heif_context_encode_image(). In unc_encoder::encode(), unc_encoder_component_interleave::encode_tile() sizes its buffer with compute_tile_data_size_bytes() using the primary dimensions but copies each component using its actual plane dimensions. The oversized alpha plane is therefore copied beyond the allocation, causing an out-of-bounds write; the inverse size mismatch can also produce an out-of-bounds read. This issue is fixed in version 1.23.1.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity53% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

August 18, 2026

Last Modified

August 21, 2026

Advisory Details (3)

Auto-updated Aug 18, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

Heap out of bounds write in libheif uncompressed encoder when writing images with mismatched auxiliary alpha dimensions · Advisory · strukturag/libheif · GitHub

https://github.com/strukturag/libheif/security/advisories/GHSA-xpw3-9rhw-482x
github_release Patch Available

v1.23.1

Patch available: strukturag/libheif v1.23.1

https://github.com/strukturag/libheif/releases/tag/v1.23.1
github_commit Patch Available

commit ac5521ad5039 (strukturag/libheif)

Patch available: strukturag/libheif v1.23.1 (contains commit ac5521ad5039)

https://github.com/strukturag/libheif/commit/ac5521ad50399885de96bb6a0733a5d2442740f9

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibheif1 (1.17.6-1ubuntu4.8) @ noble2026-08-29ubuntu

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 12× in last 7d / 22× 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. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 13:32 UTCEG score recompute
  3. 2026-08-29 13:32 UTCVendor advisory
  4. 2026-08-28 21:42 UTCEPSS rescore
  5. 2026-08-28 13:53 UTCVendor advisory
  6. 2026-08-27 14:44 UTCEG score recompute
  7. 2026-08-27 14:25 UTCEPSS rescore
  8. 2026-08-26 15:41 UTCEG score recompute
  9. 2026-08-26 14:46 UTCEPSS rescore
  10. 2026-08-25 16:36 UTCEG score recompute
  11. 2026-08-25 13:49 UTCEPSS rescore
  12. 2026-08-24 17:30 UTCEG score recompute
  13. 2026-08-22 19:26 UTCEG score recompute
  14. 2026-08-21 23:49 UTCEPSS rescore
  15. 2026-08-21 20:23 UTCEG score recompute
  16. 2026-08-21 19:20 UTCEG score recompute
  17. 2026-08-20 22:55 UTCEPSS rescore
  18. 2026-08-19 21:27 UTCEG score recompute
  19. 2026-08-19 17:04 UTCEPSS rescore
  20. 2026-08-18 22:23 UTCEG score recompute
  21. 2026-08-18 21:23 UTCEG score recompute
  22. 2026-08-18 21:23 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-62291?
CVE-2026-62291 is a medium vulnerability published on August 18, 2026. libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted image sequence with a 2x2 primary plane and a 256x256 auxiliary alpha plane can cause attacker-controlled heap corruption during a normal decode and re-encode workflow. TrackVisual::decodenextimagesample()…
When was CVE-2026-62291 disclosed?
CVE-2026-62291 was first published in the National Vulnerability Database on August 18, 2026, with the most recent update on August 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-62291 actively exploited?
CVE-2026-62291 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 97.0% of all scored CVEs.
What is the CVSS score of CVE-2026-62291?
CVE-2026-62291 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-62291?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-62291, 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

Explore the affected products and dependency analysis for CVE-2026-62291

Explore →

Is Your Infrastructure Affected by CVE-2026-62291?

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

Start Free Scan →Browse All CVEs