Upstream information
Description
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.SUSE information
Overall state of this security issue: Does not affect SUSE products
This issue is currently rated as having important severity.
| CVSS detail | CNA (GitHub) | SUSE |
|---|---|---|
| Base Score | 7.3 | 7.3 |
| Vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H |
| Attack Vector | Local | Local |
| Attack Complexity | Low | Low |
| Privileges Required | None | None |
| User Interaction | None | None |
| Scope | Unchanged | Unchanged |
| Confidentiality Impact | Low | Low |
| Integrity Impact | Low | Low |
| Availability Impact | High | High |
| CVSSv3 Version | 3.1 | 3.1 |
SUSE Timeline for this CVE
CVE page created: Wed Apr 15 02:01:13 2026CVE page last modified: Wed Apr 15 14:52:52 2026