libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a use-after-free vulnerability in sixel_encoder_encode_bytes() because sixel_frame_init() stores the caller-owned pixel buffer pointer directly in frame->pixels without making a defensive copy. When a resize operation is triggered, sixel_frame_convert_to_rgb888() unconditionally frees this caller-owned buffer and replaces it with a new internal allocation, leaving the caller with a dangling pointer. Any subsequent access to the original buffer by the caller constitutes a use-after-free, confirmed by AddressSanitizer. An attacker who controls incoming frames can trigger this bug repeatedly and predictably, resulting in a reliable crash with potential for code execution. This issue has been fixed in version 1.8.7-r1.
1.4.2-11.5.2-21.5.2-21.7.3-11.8.2-11.8.2-2.11.10.3-21.10.3-31.8.6-21.10.3-31.10.3-3build11.10.5-1Exploitability
AV:LAC:LPR:NUI:NScope
S:UImpact
C:LI:LA:HCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H