{"id":"CVE-2026-44637","state":"PUBLISHED","title":"libsixel: integer overflow in parser","description":"libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From  to 1.8.7-r1, a signed integer overflow in the SIXEL parser's image-buffer doubling loop can lead to an out-of-bounds heap write in sixel_decode_raw_impl. context->pos_x grows by repeat_count on every sixel character with no upper bound check. Once pos_x approaches INT_MAX, the expression \"pos_x + repeat_count\" used to size the image buffer overflows signed int. Depending on how the overflow wraps, the resize check that should reject oversized buffers can be bypassed, after which a subsequent write computes a large attacker-influenced offset into image->data and writes past the allocation. Reachable from any caller that decodes attacker-supplied SIXEL data, including img2sixel. This vulnerability is fixed in 1.8.7-r2.","publishedAt":"2026-05-14T20:02:32.034Z","updatedAt":"2026-05-15T13:35:45.953Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["saitoha libsixel"],"affected":[{"vendor":"saitoha","product":"libsixel","versions":[{"version":">= 0.11.0, < 1.8.7-r2","status":"affected"}]}],"references":["https://github.com/saitoha/libsixel/security/advisories/GHSA-9jm7-77gr-qghv"],"weaknesses":["CWE-190","CWE-787"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/44xxx/CVE-2026-44637.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-44637","state":"PUBLISHED","datePublished":"2026-05-14T20:02:32.034Z","dateUpdated":"2026-05-15T13:35:45.953Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-07T15:30:10.875Z"},"containers":{"cna":{"title":"libsixel: integer overflow in parser","descriptions":[{"lang":"en","value":"libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From  to 1.8.7-r1, a signed integer overflow in the SIXEL parser's image-buffer doubling loop can lead to an out-of-bounds heap write in sixel_decode_raw_impl. context->pos_x grows by repeat_count on every sixel character with no upper bound check. Once pos_x approaches INT_MAX, the expression \"pos_x + repeat_count\" used to size the image buffer overflows signed int. Depending on how the overflow wraps, the resize check that should reject oversized buffers can be bypassed, after which a subsequent write computes a large attacker-influenced offset into image->data and writes past the allocation. Reachable from any caller that decodes attacker-supplied SIXEL data, including img2sixel. This vulnerability is fixed in 1.8.7-r2."}],"affected":[{"vendor":"saitoha","product":"libsixel","versions":[{"version":">= 0.11.0, < 1.8.7-r2","status":"affected"}]}],"references":[{"url":"https://github.com/saitoha/libsixel/security/advisories/GHSA-9jm7-77gr-qghv","name":"https://github.com/saitoha/libsixel/security/advisories/GHSA-9jm7-77gr-qghv","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":7.1,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","lang":"en","description":"CWE-190: Integer Overflow or Wraparound","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787: Out-of-bounds Write","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-14T20:02:32.034Z"},"source":{"advisory":"GHSA-9jm7-77gr-qghv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/saitoha/libsixel/security/advisories/GHSA-9jm7-77gr-qghv","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-15T13:35:42.115758Z","id":"CVE-2026-44637","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-15T13:35:45.953Z"}}]}}}