Heap disclosure via uncovered uninitialized grid pixels
Published Jul 21, 2026 · Updated Jul 21, 2026
Information disclosure in libheif before 1.22.0 allows remote attackers to read process heap data via crafted grid images. The grid coverage check truncates tile widths while pixel-plane allocation leaves padding uninitialized, so uncovered canvas pixels expose stale heap bytes. Exploitation requires a crafted HEIF or AVIF file to be decoded and its output exposed; server-side transcoders can return heap data in pixels.
Summary
What happened
Information disclosure in libheif before 1.22.0 allows remote attackers to read process heap data via crafted grid images. The grid coverage check truncates tile widths while pixel-plane allocation leaves padding uninitialized, so uncovered canvas pixels expose stale heap bytes. Exploitation requires a crafted HEIF or AVIF file to be decoded and its output exposed; server-side transcoders can return heap data in pixels.
The record
- CVE
- CVE-2026-47247
- Published
- Jul 21, 2026
- Updated
- Jul 21, 2026
- Vendor
- Struktur AG
- Product
- libheif
- Classifications
- CWE-682, CWE-226, CWE-908, CWE-200, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.22.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- poc-files.tar.gz crafted grid-image proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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