Vulnerability · Published May 19, 2026 · Assigned by GitHub_M
CVE-2026-32741libheif has a heap buffer overflow in decode_mask_image()
High 7.1
In plain English
A high-severity heap buffer overflow in libheif from strukturag. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
libheif is a HEIF and AVIF file format decoder and encoder. Versions 1.21.2 and below contain a heap buffer overflow in MaskImageCodec::decode_mask_image(). When decoding a HEIF file containing a mask image (mski), the function copies the full iloc extent data into a pixel buffer using memcpy(dst, data.data(), data.size()). The copy length data.size() is determined by the iloc extent in the file (attacker-controlled), while the destination buffer is sized based on the declared image dimensions. Because no upper-bound check exists on the data length, a crafted file whose iloc extent exceeds the pixel buffer allocation overflows the heap. The vulnerable single-memcpy branch is reached when the mskC property specifies bits_per_pixel = 8 and the ispe property declares an even width ≥ 64 (so that stride == width), with no changes to default security limits or external codec plugins required. This issue has been fixed in version 1.22.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libheif | no fix listed | DEBIAN-CVE-2026-32741 |
| Debian:13 | libheif | 1.19.8-1+deb13u1 | DEBIAN-CVE-2026-32741 |
| Debian:14 | libheif | 1.23.1-1 | DEBIAN-CVE-2026-32741 |
| Ubuntu:24.04:LTS | libheif | 1.17.6-1ubuntu4.4 | UBUNTU-CVE-2026-32741 |
| Ubuntu:25.10 | libheif | 1.20.2-1ubuntu0.4 | UBUNTU-CVE-2026-32741 |
| Ubuntu:26.04:LTS | libheif | 1.21.2-3ubuntu0.1 | UBUNTU-CVE-2026-32741 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| strukturag | libheif | < 1.22.0 |
Weakness: CWE-122, CWE-120 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
References
- https://github.com/strukturag/libheif/security/advisories/GHSA-j3w5-7whq-p37q x_refsource_CONFIRM
- https://github.com/strukturag/libheif/releases/tag/v1.22.0 x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-32741 vdb-entry, x_refsource_REDHAT
- RHBZ#2480002 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32741.json x_sadp-csaf-vex