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CVE-2026-32741

libheif has a heap buffer overflow in decode_mask_image() PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
strukturag / libheifaffected < 1.22.0

CWE

CWE-122

References

ADP enrichment

CISA-ADP

No English description supplied.

redhat-SADP

A flaw was found in libheif, a library for decoding and encoding HEIF (High Efficiency Image File Format) and AVIF files. A remote attacker could exploit a heap buffer overflow vulnerability in the MaskImageCodec::decode_mask_image() function by providing a specially crafted HEIF file containing a mask image. This vulnerability occurs because the function copies image data into a buffer without proper size validation, allowing the attacker-controlled input to exceed the allocated memory. Successful exploitation can lead to a denial of service (DoS) and potentially other impacts due to memory corruption.