CVE-2026-44637— libsixel: integer overflow in parser

libsixel: integer overflow in parser

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a signed integer overflow in the SIXEL parser's image-buffer doubling loop can lead to an out-of-bounds heap write in sixel_decode_raw_impl. context->pos_x grows by repeat_count on every sixel character with no upper bound check. Once pos_x approaches INT_MAX, the expression "pos_x + repeat_count" used to size the image buffer overflows signed int. Depending on how the overflow wraps, the resize check that should reject oversized buffers can be bypassed, after which a subsequent write computes a large attacker-influenced offset into image->data and writes past the allocation. Reachable from any caller that decodes attacker-supplied SIXEL data, including img2sixel. This vulnerability is fixed in 1.8.7-r2.

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

整数溢出或超界折返

libsixel 输入验证错误漏洞

libsixel是Hayaki Saito个人开发者的一个为DEC SIXEL图形和其他转换器程序提供编码/解码实现的软件包。 libsixel 1.8.7-r1及之前版本存在输入验证错误漏洞，该漏洞源于SIXEL解析器图像缓冲区加倍循环中的有符号整数溢出，可能导致越界堆写入。

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