{"id":"CVE-2021-44718","aliases":["DEBIAN-CVE-2021-44718","EUVD-2021-31533","GHSA-9m99-gmcj-9g66","JLSEC-2026-668","UBUNTU-CVE-2021-44718"],"status":"published","title":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the...","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.00787,"percentile":0.56462,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-835"],"published":"2022-09-02T11:11:14Z","modified":"2026-10-23T18:02:30Z","fixes":[{"ecosystem":"Debian:12","package":"wolfssl","fixed_in":["5.1.1-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"wolfssl","fixed_in":["5.1.1-1"],"sources":["osv"]},{"ecosystem":"Julia","package":"wolfSSL_jll","fixed_in":["5.7.2+0"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.1.1-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.1.1-1"}]}]},{"source":"osv","ecosystem":"Julia","package":"wolfSSL_jll","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.7.2+0"}]}]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.4.8+dfsg-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10.2+dfsg-2","3.12.0+dfsg-1","3.12.2+dfsg-1","3.13.0+dfsg-1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg-2","4.2.0+dfsg-1","4.2.0+dfsg-2","4.2.0+dfsg-3","4.3.0+dfsg-2"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.6.0-3","5.0.0-1","5.1.1-1","5.2.0-1","5.2.0-2"]}],"products":[{"vendor":"wolfssl","product":"wolfssl"}],"references":[{"url":"https://www.wolfssl.com/docs/security-vulnerabilities/","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory","web"]},{"url":"https://github.com/wolfSSL/wolfssl/releases","tags":["x_refsource_MISC","x_transferred","Release Notes","Third Party Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-44718"},{"url":"https://github.com/advisories/GHSA-9m99-gmcj-9g66"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-44718","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-44718","tags":["report"]},{"url":"https://github.com/wolfSSL/wolfssl/pull/4629","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-44718","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-44718","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2022-09-02T11:11:14Z","modified":"2024-08-04T04:32:12.226Z","updated_at":"2026-11-02T14:33:01.166399Z"}],"euvd":[{"id":"EUVD-2021-31533","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2022-09-02T11:11:14Z","modified":"2024-08-04T04:32:12Z","updated_at":"2026-11-03T03:08:28.560815Z"}],"ghsa":[{"id":"GHSA-9m99-gmcj-9g66","title":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the...","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2022-09-03T00:00:25Z","modified":"2023-01-29T05:06:03Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:45:56.147373Z"}],"nvd":[{"id":"CVE-2021-44718","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2022-09-02T12:15:09.337Z","modified":"2026-06-17T04:12:45.727Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:07:06.906968Z"}],"osv":[{"id":"CVE-2021-44718","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2022-09-02T12:15:09.337Z","modified":"2026-10-20T10:55:06.868909671Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:21.877444Z"},{"id":"DEBIAN-CVE-2021-44718","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2022-09-02T12:15:09.337Z","modified":"2026-10-23T18:02:30.867905858Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:35.799676Z"},{"id":"JLSEC-2026-668","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2026-07-14T21:41:35.775Z","modified":"2026-07-18T00:02:19.783843762Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:47:19.003546Z"},{"id":"UBUNTU-CVE-2021-44718","description":"wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.","status":"published","published":"2022-09-02T12:15:00Z","modified":"2026-04-22T13:02:59.052878Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:54:29.220315Z"}]}}