CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
The life of this vulnerability
- CVE published
- Last sighting4mo
Gaps are compressed to equal steps. The elapsed time is printed under each.
Which catalogues call it exploited
- CISA KEVUS federaldoes not list it
- EUVDENISA, European Uniondoes not list it
- VulnCheck KEVcommercial researchdoes not list it
- CIRCLaggregator, mirrors the abovelisted Sep 18, 2026, not counted
Only CIRCL, an aggregator, carries this listing. No primary catalogue we count has confirmed exploitation, so no patch window is computed.
Public exploitation evidence
- exploitedvulnerability.circl.lu/known-exploited-vulnerabilities-catal
- seengist.github.com/ichintu/5841827a4cd9286d1b1bda016e23c9f0
- seenbsky.app/profile/cve.skyfleet.blue/post/3mmahdobytv2e
3 public reports collected from VulnCheck and CIRCL, first on May 19, 2026. Each links to its original source. We have not verified them.
Description
libheif is a HEIF and AVIF file format decoder and encoder. Versions 1.21.2 and prior contain a heap buffer over-read in HeifPixelImage::overlay() in libheif/pixelimage.cc. When compositing an overlay image (iovl) whose child image has a different bit depth for the alpha channel than for the color channels, the function indexes into the alpha plane using the color channel stride (in_stride) instead of the previously retrieved alpha_stride, causing reads past the end of the alpha buffer (up to 3,123 bytes for a 100×50 image with 10-bit color and 8-bit alpha). A crafted HEIF file can exploit this to cause a denial of service (crash) or potentially disclose adjacent heap memory through leaked b