How severe is CVE-2026-47251?

CVE-2026-47251 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability high.

Is CVE-2026-47251 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-47251?

CVE-2026-47251 affects Struktur Libheif. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-47251?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-47251 published?

CVE-2026-47251 was published on 2026-07-21 and last updated on 2026-07-27.

CVE-2026-47251

CVE-2026-47251 is a medium-severity vulnerability in Struktur Libheif with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 6.8
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Struktur Libheif
Published: 2026-07-21
Last modified: 2026-07-27

Description

libheif is a HEIF and AVIF file format decoder and encoder. The fix for CVE-2026-3949 (commit `b97c8b5`, PR #1712) introduced an integer overflow in the very security check it added. The check itself can be bypassed, allowing a crafted HEIF file with a VVC track to trigger the same out-of-bounds heap read that CVE-2026-3949 was meant to prevent. This is a separate, currently-unpatched vulnerability. Issue #1712 was closed as fixed without testing the edge case where `size` is near `UINT32_MAX`. Version 1.22.0 patches the issue.

Frequently asked questions

What is CVE-2026-47251?: libheif is a HEIF and AVIF file format decoder and encoder. The fix for CVE-2026-3949 (commit `b97c8b5`, PR #1712) introduced an integer overflow in the very security check it added. The check itself can be bypassed, allowing a crafted HEIF file with a VVC track to trigger the same out-of-bounds heap read that CVE-2026-3949 was meant to prevent. This is a separate, currently-unpatched vulnerability. Issue #1712 was closed as fixed without testing the edge case where `size` is near `UINT32_MAX`. Version 1.22.0 patches the issue.
How severe is CVE-2026-47251?: CVE-2026-47251 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability high.
Is CVE-2026-47251 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-47251?: CVE-2026-47251 affects Struktur Libheif. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-47251?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-47251 published?: CVE-2026-47251 was published on 2026-07-21 and last updated on 2026-07-27.

References

Affected products (1)

cpe:2.3:a:struktur:libheif:*:*:*:*:*:*:*:*

More vulnerabilities in Struktur Libheif

CVE-2026-32740 — High (CVSS 8.8): libheif is a HEIF and AVIF file format decoder and encoder. Versions 1.21.2 and prior contain a heap-buffer-overflow…
CVE-2023-49464 — High (CVSS 8.8): libheif v1.17.5 was discovered to contain a segmentation violation via the function…
CVE-2023-49463 — High (CVSS 8.8): libheif v1.17.5 was discovered to contain a segmentation violation via the function find_exif_tag at /libheif/exif.cc.
CVE-2023-49462 — High (CVSS 8.8): libheif v1.17.5 was discovered to contain a segmentation violation via the component /libheif/exif.cc.
CVE-2023-49460 — High (CVSS 8.8): libheif v1.17.5 was discovered to contain a segmentation violation via the function…
CVE-2020-19499 — High (CVSS 8.8): An issue was discovered in heif::Box_iref::get_references in libheif 1.4.0, allows attackers to cause a Denial of…

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Other CWE-125 (Out-of-bounds Read) vulnerabilities

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