CVE-2025-68431

Unknown Unknown - Not Provided

Heap Buffer Over-Read in libheif Overlay Image Processing Causes Crash

Publication date: 2025-12-29

Last updated on: 2026-02-25

Assigner: GitHub, Inc.

Description

libheif is an HEIF and AVIF file format decoder and encoder. Prior to version 1.21.0, a crafted HEIF that exercises the overlay image item path triggers a heap buffer over-read in `HeifPixelImage::overlay()`. The function computes a negative row length (likely from an unclipped overlay rectangle or invalid offsets), which then underflows when converted to `size_t` and is passed to `memcpy`, causing a very large read past the end of the source plane and a crash. Version 1.21.0 contains a patch. As a workaround, avoid decoding images using `iovl` overlay boxes.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-12-29

Last Modified

2026-02-25

Generated

2026-07-06

AI Q&A

2025-12-29

EPSS Evaluated

2026-07-05

NVD

CVE-2025-68431

Affected Vendors & Products

Vendor	Product	Version / Range
struktur	libheif	to 1.21.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-125	The product reads data past the end, or before the beginning, of the intended buffer.
CWE-190	The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

Executive Summary

This vulnerability in libheif occurs when a specially crafted HEIF file uses the overlay image item path, causing the function HeifPixelImage::overlay() to compute a negative row length. This negative value underflows when converted to an unsigned size_t type and is passed to memcpy, resulting in a heap buffer over-read and a crash.

Impact Analysis

The vulnerability can cause a crash in applications using libheif to decode crafted HEIF images, potentially leading to denial of service. It does not impact confidentiality or integrity but affects availability.

Mitigation Strategies

To mitigate this vulnerability, update libheif to version 1.21.0 or later where the issue is patched. As a workaround, avoid decoding images that use 'iovl' overlay boxes.

Compliance Impact

The provided information does not specify how this vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

Detection Guidance

This vulnerability can be detected by testing the libheif library with crafted HEIF images that exercise the overlay image item path, specifically those using 'iovl' overlay boxes. Detection involves observing crashes or abnormal behavior during image decoding. Since the vulnerability causes a heap buffer over-read leading to crashes, running libheif decoding under memory error detection tools like AddressSanitizer or using fuzzing tools such as libFuzzer can help identify the issue. There are no specific network commands provided, but you can check the libheif version installed on your system with commands like 'libheif --version' or by querying your package manager (e.g., 'dpkg -l | grep libheif' on Debian-based systems). To detect vulnerable versions, ensure the libheif version is earlier than 1.21.0. Avoid decoding HEIF images with overlay boxes as a workaround. No explicit commands for detection are provided in the resources. [3]

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