CVE-2026-33023
- Source
- https://cve.org/CVERecord?id=CVE-2026-33023
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33023.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-33023
- Aliases
-
- GHSA-hr25-g2j6-qjw6
- Downstream
- Published
- 2026-04-14T22:05:31Z
- Modified
- 2026-08-12T03:51:21Z
- 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
- libsixel: Use-after-free in load_with_gdkpixbuf()
- 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.
- Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-416" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33023.json" }- References
Affected packages
Git / github.com/saitoha/libsixel
Affected ranges
- Type
- GIT
- Repo
- https://github.com/saitoha/libsixel
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedFixed
- Database specific
-
Show details
{ "cpe": "cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*", "extracted_events": [ { "introduced": "0" }, { "last_affected": "1.8.7" } ], "source": [ "CPE_RANGE", "REFERENCES" ] }