DEBIAN-CVE-2026-33023
- Source
- https://security-tracker.debian.org/tracker/CVE-2026-33023
- Import Source
- https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33023.json
- JSON Data
- https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-33023
- Upstream
- Published
- 2026-04-14T23:16:27Z
- Modified
- 2026-09-14T17:03:08Z
- Severity
-
- 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H CVSS Calculator
- Summary
- [none]
- Details
-
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. In versions 1.8.7 and prior, when built with the --with-gdk-pixbuf2 option, a use-after-free vulnerability exists in load_with_gdkpixbuf() in loader.c. The cleanup path manually frees the sixel_frame_t object and its internal buffers without consulting the reference count, even though the object was created via the refcounted constructor sixel_frame_new() and exposed to the public callback. A callback that calls sixel_frame_ref(frame) to retain a logically valid reference will hold a dangling pointer after sixel_helper_load_image_file() returns, and any subsequent access to the frame or its fields triggers a use-after-free confirmed by AddressSanitizer. The root cause is a consistency failure between two cleanup strategies in the same codebase: sixel_frame_unref() is used in load_with_builtin() but raw free() is used in load_with_gdkpixbuf(). An attacker supplying a crafted image to any application built against libsixel with gdk-pixbuf2 support can trigger this reliably, potentially leading to information disclosure, memory corruption, or 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