High severity · published Jul 21, 2026
CVE-2026-47247
libheif Vulnerable to Heap Information Disclosure via Grid Image Gap + Uninitialized Pixel Plane Allocation
7.5
CVSS
0.5%
EPSS
No
On KEV
Description
libheif is a HEIF and AVIF file format decoder and encoder. Prior to version 1.22.0, two bugs in libheif chain to leak process heap memory as visible pixel values in decoded grid images. An attacker who uploads a crafted AVIF/HEIC file to any server-side image processor (WordPress, Sharp/libvips, ImageMagick, etc.) can recover heap data - including library function pointers sufficient to defeat ASLR, or any other secret - from the publicly-downloadable transcoded JPEG/PNG/WebP output. Local attack vectors are also possible. Version 1.22.0 fixes the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
libheif · strukturag
< 1.22.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-47247
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-47247
Exploit
https://github.com/strukturag/libheif/security/advisories/GHSA-2vh6-whr3-cmq3
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