DEBIAN-CVE-2026-33021
- Source
- https://security-tracker.debian.org/tracker/CVE-2026-33021
- Import Source
- https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33021.json
- JSON Data
- https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-33021
- Upstream
- Published
- 2026-04-14T23:16:27Z
- Modified
- 2026-09-14T17:03:08Z
- Severity
-
- 7.3 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H CVSS Calculator
- Summary
- [none]
- Details
-
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.
- References
Affected packages
Debian:12 / libsixel
Package
- Name
- libsixel
- Purl
- pkg:deb/debian/libsixel?arch=source&distro=bookworm
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affected
Debian:13 / libsixel
Package
- Name
- libsixel
- Purl
- pkg:deb/debian/libsixel?arch=source&distro=trixie
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affected
Debian:14 / libsixel
Package
- Name
- libsixel
- Purl
- pkg:deb/debian/libsixel?arch=source&distro=forky