CVE-2026-32741

High

Published: 19 May 2026

Published

19 May 2026

Modified

20 May 2026

KEV Added

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Patch

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CVSS Score v3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H

EPSS Score 0.0027 18.4th percentile

Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-32741 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Malicious File (T1204.002); ranked at the 18.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-30982

Vulnerability details

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.

CWE(s): CWE-122

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1204.002 Malicious File Execution

An adversary may rely upon a user opening a malicious file in order to gain execution.

attack.mitre.org →

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Heap buffer overflow in HEIF/AVIF decoder triggered by attacker-controlled crafted file (iloc extent size) enables user execution via malicious file or exploitation of public-facing apps processing such files.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1