Heap-based Buffer Overflow Affecting libheif package, versions <1.17.6-1ubuntu4.4


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.34% (27th percentile)

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  • Snyk IDSNYK-UBUNTU2404-LIBHEIF-16780735
  • published17 Jun 2026
  • disclosed19 May 2026

Introduced: 19 May 2026

CVE-2026-32741  (opens in a new tab)
CWE-122  (opens in a new tab)

How to fix?

Upgrade Ubuntu:24.04 libheif to version 1.17.6-1ubuntu4.4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libheif package and not the libheif package as distributed by Ubuntu. See How to fix? for Ubuntu:24.04 relevant fixed versions and status.

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 Base Scores

version 3.1