libheif is a HEIF and AVIF file format decoder and encoder. Versions 1.21.2 and below contain a heap buffer overflow in MaskImageCodec::decodemaskimage(). 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 bitsperpixel = 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.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32741.json",
"cwe_ids": [
"CWE-122"
],
"cna_assigner": "GitHub_M"
}[
{
"id": "CVE-2026-32741-91619f1d",
"target": {
"file": "tests/uncompressed_box.cc"
},
"deprecated": false,
"digest": {
"threshold": 0.9,
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},
"signature_version": "v1",
"source": "https://github.com/strukturag/libheif/commit/0c81a846b7401dbdb7118afd0761057f21e43511",
"signature_type": "Line"
}
]
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-32741.json"
"2026-08-12T15:33:08Z"