{"id":"CVE-2026-44637","aliases":["DEBIAN-CVE-2026-44637","EUVD-2026-30412","GHSA-9jm7-77gr-qghv","UBUNTU-CVE-2026-44637","openSUSE-SU-2026:12420-1"],"status":"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-\u003epos_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-\u003edata 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.","severity":{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0016,"percentile":0.05193,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-190","CWE-787"],"published":"2026-05-14T20:02:32Z","modified":"2026-11-05T17:27:03Z","fixes":[{"ecosystem":"Debian:14","package":"libsixel","fixed_in":["1:1.8.7-r2-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.3-3","1.10.5-1","1:1.8.7-1","1:1.8.7-2","1:1.8.7-3","1:1.8.7-4","1:1.8.7-5","1:1.8.7-6","1:1.8.7-r2-1"]},{"source":"osv","ecosystem":"Debian:13","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.5-1","1:1.8.7-1","1:1.8.7-2","1:1.8.7-3","1:1.8.7-4","1:1.8.7-5","1:1.8.7-6","1:1.8.7-r2-1"]},{"source":"osv","ecosystem":"Debian:14","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.8.7-r2-1"}]}],"versions":["1.10.5-1","1:1.8.7-1","1:1.8.7-2","1:1.8.7-3","1:1.8.7-4","1:1.8.7-5","1:1.8.7-6"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.2-1","1.5.2-2"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.2-2","1.7.3-1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.2-1","1.8.2-2.1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.6-2","1.10.3-2","1.10.3-3"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.3-3","1.10.3-3build1"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.5-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.5-1build1","1:1.8.7-r2-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.5-1","1.10.5-1build1"]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"libsixel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.10.5-3.1"}]}],"bundled":4}],"products":[{"vendor":"saitoha","product":"libsixel"}],"references":[{"url":"https://github.com/saitoha/libsixel/security/advisories/GHSA-9jm7-77gr-qghv","tags":["x_refsource_CONFIRM","exploit","Exploit","Vendor Advisory","advisory","report"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44637.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44637","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-44637","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-44637","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-44637","tags":["report"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2026-33023","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-44636","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-44637","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-44638","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2026-44637","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-\u003epos_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-\u003edata 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.","status":"published","published":"2026-05-14T20:02:32.034Z","modified":"2026-05-15T13:35:45.953Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-190","CWE-787"],"updated_at":"2026-11-02T13:42:49.132798Z"}],"euvd":[{"id":"EUVD-2026-30412","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-\u003epos_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-\u003edata 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.","status":"published","published":"2026-05-14T20:02:32Z","modified":"2026-05-15T13:35:45Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T19:04:28.872228Z"}],"nvd":[{"id":"CVE-2026-44637","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-\u003epos_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-\u003edata 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.","status":"published","published":"2026-05-14T20:17:08.847Z","modified":"2026-10-26T14:10:00.13Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-190","CWE-787"],"updated_at":"2026-11-02T14:12:19.39893Z"}],"osv":[{"id":"CVE-2026-44637","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-\u003epos_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-\u003edata 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.","status":"published","published":"2026-05-14T20:02:32.034Z","modified":"2026-11-05T17:27:03.969808903Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high"}],"cwes":["CWE-190","CWE-787"],"updated_at":"2026-11-05T17:54:30.87969Z"},{"id":"DEBIAN-CVE-2026-44637","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-\u003epos_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-\u003edata 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.","status":"published","published":"2026-05-14T20:17:08.847Z","modified":"2026-10-27T09:47:33.70189181Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:55.669088Z"},{"id":"UBUNTU-CVE-2026-44637","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-\u003epos_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-\u003edata 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.","status":"published","published":"2026-05-14T20:17:00Z","modified":"2026-10-17T12:58:21.638775006Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T16:56:26.396868Z"},{"id":"openSUSE-SU-2026:12420-1","title":"libsixel-bash-completion-1.10.5-3.1 on GA media","description":"These are all security issues fixed in the libsixel-bash-completion-1.10.5-3.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-11-04T00:00:00Z","modified":"2026-11-05T17:23:17.517885405Z","updated_at":"2026-11-05T17:55:05.69587Z"}]}}