CVE-2026-33018

{"id": "CVE-2026-33018", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33018", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-04-16T13:52:34.921283Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.0, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.0}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "saitoha", "product": "libsixel", "versions": [{"status": "affected", "version": "< 1.8.7-rc1"}]}]}], "published": "2026-04-14T22:16:30.213", "references": [{"url": "https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1", "tags": ["Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/saitoha/libsixel/security/advisories/GHSA-w46f-jr9f-rgvp", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-416"}]}], "descriptions": [{"lang": "en", "value": "libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a Use-After-Free vulnerability via the load_gif() function in fromgif.c, where a single sixel_frame_t object is reused across all frames of an animated GIF and gif_init_frame() unconditionally frees and reallocates frame->pixels between frames without consulting the object's reference count. Because the public API explicitly provides sixel_frame_ref() to retain a frame and sixel_frame_get_pixels() to access the raw pixel buffer, a callback following this documented usage pattern will hold a dangling pointer after the second frame is decoded, resulting in a heap use-after-free confirmed by ASAN. Any application using sixel_helper_load_image_file() with a multi-frame callback to process user-supplied animated GIFs is affected, with a reliable crash as the minimum impact and potential for code execution. This issue has been fixed in version 1.8.7-r1."}, {"lang": "es", "value": "libsixel es una implementaci\u00f3n de codificador/decodificador SIXEL derivada de sixel de kmiya. Las versiones 1.8.7 y anteriores contienen una vulnerabilidad de uso despu\u00e9s de liberaci\u00f3n a trav\u00e9s de la funci\u00f3n load_gif() en fromgif.c, donde un \u00fanico objeto sixel_frame_t se reutiliza en todos los fotogramas de un GIF animado y gif_init_frame() libera y reasigna incondicionalmente frame -> pixels entre fotogramas sin consultar el contador de referencias del objeto. Debido a que la API p\u00fablica proporciona expl\u00edcitamente sixel_frame_ref() para retener un fotograma y sixel_frame_get_pixels() para acceder al b\u00fafer de p\u00edxeles sin procesar, una devoluci\u00f3n de llamada que siga este patr\u00f3n de uso documentado mantendr\u00e1 un puntero colgante despu\u00e9s de que se decodifique el segundo fotograma, lo que resultar\u00e1 en un uso despu\u00e9s de liberaci\u00f3n en el heap confirmado por ASAN. Cualquier aplicaci\u00f3n que utilice sixel_helper_load_image_file() con una devoluci\u00f3n de llamada multifotograma para procesar GIFs animados proporcionados por el usuario se ve afectada, con un bloqueo fiable como el impacto m\u00ednimo y potencial de ejecuci\u00f3n de c\u00f3digo. Este problema ha sido solucionado en la versi\u00f3n 1.8.7-r1."}], "lastModified": "2026-07-25T10:10:00.167", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E16EAA6A-544F-4D16-829D-1B7C9979EA6A", "versionEndExcluding": "1.8.7-r1"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}