CVE-2026-32741
Versions 1.21.2 and below contain a heap buffer overflow in MaskImageCodec::decode_mask_image().
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.34%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.1 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
- EPSS
- 0.34% probability · 28th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-122, CWE-120
- Source
- security-advisories@github.com
References
- https://github.com/strukturag/libheif/releases/tag/v1.22.0
- https://github.com/strukturag/libheif/security/advisories/GHSA-j3w5-7whq-p37q
- https://access.redhat.com/security/cve/CVE-2026-32741
- https://bugzilla.redhat.com/show_bug.cgi?id=2480002
- https://github.com/strukturag/libheif/security/advisories/GHSA-j3w5-7whq-p37q
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32741.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.