{"id":"CVE-2026-44638","summary":"libsixel: NULL pointer dereference","details":"libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From  to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.","aliases":["GHSA-wpx3-h5g8-qr3w"],"modified":"2026-08-12T03:51:27.490161804Z","published":"2026-05-14T19:59:29.704Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44638.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-476","CWE-690"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44638.json"},{"type":"ADVISORY","url":"https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44638"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/saitoha/libsixel","events":[{"introduced":"cf6b1c58f7505dec57de0f901bf23b67f5a4e316"},{"fixed":"764f4e618c8bbc427fb74622e3227243fe6762fb"}],"database_specific":{"extracted_events":[{"introduced":"1.0.0"},{"fixed":"1.8.7-r2"}],"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*"}}],"versions":["v1.8.7-r1","v1.8.7","nightly-latest","v1.8.6","v1.8.5","v1.8.4","v1.8.3","v1.8.2","v1.8.1","v1.8.0","v1.7.3","v1.7.2","v1.7.1","v1.6.1","v1.5.2","v1.5.1","v1.5.0","v1.4.13","v1.4.12","v1.4.11","v1.4.10","v1.4.9","v1.4.8","v1.4.7","v1.4.6","v1.4.5","v1.4.4","v1.4.3","v1.4.2","v1.4.1","v1.4.0","v1.3.6","v1.3.5","v1.3.4","v1.3.3","v1.3.2","v1.3.1","v1.1.2","v1.1.1","v1.1.0","v1.0.2","v1.0.1","v1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44638.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L"}]}