CVE-2026-33021
- Source
- https://cve.org/CVERecord?id=CVE-2026-33021
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33021.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-33021
- Aliases
-
- GHSA-j6m5-2cc7-3whc
- Downstream
- Published
- 2026-04-14T21:57:22Z
- Modified
- 2026-08-12T03:51:34Z
- 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
- libsixel: Use-after-free in sixel_encoder_encode_bytes()
- 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.
- Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-416" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33021.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" }, { "fixed": "1.8.7-r1" } ], "source": [ "AFFECTED_FIELD", "CPE_RANGE", "REFERENCES" ] }