{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33023","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-03-17T17:22:14.667Z","datePublished":"2026-04-14T22:05:31.493Z","dateUpdated":"2026-04-15T20:02:36.839Z"},"containers":{"cna":{"title":"libsixel: Use-after-free in load_with_gdkpixbuf()","problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","description":"CWE-416: Use After Free","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":7.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"name":"https://github.com/saitoha/libsixel/security/advisories/GHSA-hr25-g2j6-qjw6","tags":["x_refsource_CONFIRM"],"url":"https://github.com/saitoha/libsixel/security/advisories/GHSA-hr25-g2j6-qjw6"},{"name":"https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1","tags":["x_refsource_MISC"],"url":"https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1"}],"affected":[{"vendor":"saitoha","product":"libsixel","versions":[{"version":"< 1.8.7-r1","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-04-14T22:05:31.493Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-hr25-g2j6-qjw6","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/saitoha/libsixel/security/advisories/GHSA-hr25-g2j6-qjw6","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-15T18:48:25.027963Z","id":"CVE-2026-33023","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-04-15T20:02:36.839Z"}}]}}