{"id":"CVE-2021-26713","aliases":["ALPINE-CVE-2021-26713","EUVD-2021-13502","GHSA-24f6-gm96-3c56","UBUNTU-CVE-2021-26713"],"status":"published","title":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x...","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-12","score":0.01868,"percentile":0.79633,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-787"],"published":"2021-02-19T19:30:30Z","modified":"2026-10-24T10:30:48Z","fixes":[{"ecosystem":"Alpine:v3.12","package":"asterisk","fixed_in":["16.16.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.13","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.14","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.15","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.16","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.17","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.18","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.19","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.20","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.21","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.22","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.23","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"asterisk","fixed_in":["18.2.1-r0"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Alpine:v3.12","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"16.16.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.13","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.14","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.15","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.16","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.17","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.18","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.19","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.20","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.21","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.22","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.23","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.24","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"16.0.0"},{"fixed":"18.2.1-r0"}]}]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:16.16.1~dfsg-2","1:16.16.1~dfsg-4","1:16.16.1~dfsg-4build1","1:16.16.1~dfsg+~2.10-1","1:18.10.0~dfsg+~cs6.10.40431411-2"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:20.4.0~dfsg+~cs6.13.40431414-2","1:20.5.0~dfsg+~cs6.13.40431414-1","1:20.5.1~dfsg+~cs6.13.40431414-1","1:20.5.2~dfsg+~cs6.13.40431414-1","1:20.6.0~dfsg+~cs6.13.40431414-1","1:20.6.0~dfsg+~cs6.13.40431414-2","1:20.6.0~dfsg+~cs6.13.40431414-2build3","1:20.6.0~dfsg+~cs6.13.40431414-2build4","1:20.6.0~dfsg+~cs6.13.40431414-2build5"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:22.2.0~dfsg+~cs6.15.60671435-2","1:22.3.0~dfsg+~cs6.15.60671435-1","1:22.4.1~dfsg+~cs6.15.60671435-1","1:22.4.1~dfsg+~cs6.15.60671435-2","1:22.5.1~dfsg+~cs6.15.60671435-1","1:22.5.2~dfsg+~cs6.15.60671435-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"asterisk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:22.5.2~dfsg+~cs6.15.60671435-1","1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu2","1:22.10.0+dfsg+~cs6.17.606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Advisory","advisory","report"]},{"url":"https://downloads.asterisk.org/pub/security/AST-2021-004.html","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory","report"]},{"url":"https://issues.asterisk.org/jira/browse/ASTERISK-29205","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-26713"},{"url":"https://github.com/advisories/GHSA-24f6-gm96-3c56"},{"url":"https://security.alpinelinux.org/vuln/CVE-2021-26713","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-26713","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-26713","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-26713","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","status":"published","published":"2021-02-19T19:30:30Z","modified":"2024-08-03T20:33:40.66Z","updated_at":"2026-11-02T14:32:57.033395Z"}],"euvd":[{"id":"EUVD-2021-13502","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","status":"published","published":"2021-02-19T19:30:30Z","modified":"2024-08-03T20:33:40Z","updated_at":"2026-11-03T03:24:51.40664Z"}],"ghsa":[{"id":"GHSA-24f6-gm96-3c56","title":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x...","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","status":"published","published":"2022-05-24T17:42:42Z","modified":"2023-01-29T05:05:29Z","cwes":["CWE-787"],"updated_at":"2026-11-02T14:45:48.396935Z"}],"nvd":[{"id":"CVE-2021-26713","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","status":"published","published":"2021-02-19T20:15:13.193Z","modified":"2026-06-17T03:43:42.467Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:06:50.031227Z"}],"osv":[{"id":"ALPINE-CVE-2021-26713","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","status":"published","published":"2021-02-19T20:15:13.193Z","modified":"2026-10-23T17:17:56.163632267Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:27:48.646074Z"},{"id":"CVE-2021-26713","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","status":"published","published":"2021-02-19T20:15:13.193Z","modified":"2026-10-24T10:30:48.216071072Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:18.778776Z"},{"id":"UBUNTU-CVE-2021-26713","description":"A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.","status":"published","published":"2021-02-19T20:15:00Z","modified":"2026-10-17T12:57:12.003194728Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:54:26.779273Z"}]}}