CVE-2026-44636
7.8
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploitability: 1.8 / Impact: 5.9
Source: NVD
Description
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, signed integer overflow in sixel_encode_highcolor's allocation size calculation can lead to a heap buffer overflow. The public sixel_encode entry point validates only that width and height are greater than zero, with no upper bound. width and height are multiplied as plain int when computing the allocation size for paletted_pixels and normalized_pixels. Any caller that asks libsixel to encode a pixel buffer with width times height greater than INT_MAX (about 2.15 billion) will hit a wrapped allocation size; under the right wrap, the malloc succeeds with a buffer much smaller than the encoder expects, and the encoder writes past the end of the heap allocation. This vulnerability is fixed in 1.8.7-r2.
Affected (1)
Related CWEs
CWE-122
Heap-based Buffer Overflow
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
CWE-190
Integer Overflow or Wraparound
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.
References (2)
Source: security-advisories@github.com
Vendor Advisory
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Vendor Advisory
Timeline
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