{"id":"CVE-2026-34873","aliases":["DEBIAN-CVE-2026-34873","EUVD-2026-18064","GHSA-q24g-gcpv-7264","ROOT-OS-DEBIAN-12-CVE-2026-34873","UBUNTU-CVE-2026-34873","openSUSE-SU-2026:10498-1"],"status":"published","title":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while...","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"adp","from":"cve"},"epss":{"day":"2026-11-09","score":0.00251,"percentile":0.16525,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-287"],"published":"2026-04-01T00:00:00Z","modified":"2026-10-28T02:31:13Z","fixes":[{"ecosystem":"Debian:13","package":"mbedtls","fixed_in":["3.6.6-0.1~deb13u1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"mbedtls","fixed_in":["3.6.6-0.1"],"sources":["osv"]},{"ecosystem":"Root:Debian:12","package":"mbedtls","fixed_in":["2.28.3-1.root.io.16","2.28.3-1.aikido.17"],"sources":["osv"]},{"ecosystem":"Root:Debian:12","package":"rootio-mbedtls","fixed_in":["2.28.3-1.root.io.16","2.28.3-1.aikido.17"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.28.3-1","2.28.4-1","2.28.5-1","2.28.6-1","2.28.7-1","2.28.7-1.1","2.28.7-1.1~exp1","2.28.8-1","3.6.0-1","3.6.0-2","3.6.0-3","3.6.2-1","3.6.2-2","3.6.2-3","3.6.3-1","3.6.4-1","3.6.4-2","3.6.5-0.1","3.6.5-0.1~deb13u1","3.6.6-0.1","3.6.6-0.1~deb13u1","3.6.7-2","3.6.7-3"]},{"source":"osv","ecosystem":"Debian:13","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.6.6-0.1~deb13u1"}]}],"versions":["3.6.4-2","3.6.5-0.1","3.6.5-0.1~deb13u1"]},{"source":"osv","ecosystem":"Debian:14","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.6.6-0.1"}]}],"versions":["3.6.4-2","3.6.5-0.1","3.6.5-0.1~deb13u1","3.6.6-0.1~deb13u1"]},{"source":"osv","ecosystem":"Root:Debian:12","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.28.3-1.root.io.16"},{"fixed":"2.28.3-1.aikido.17"}]}]},{"source":"osv","ecosystem":"Root:Debian:12","package":"rootio-mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.28.3-1.root.io.16"},{"fixed":"2.28.3-1.aikido.17"}]}]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1.2-1","2.2.0-1","2.2.1-1","2.2.1-2","2.2.1-2ubuntu0.1","2.2.1-2ubuntu0.2","2.2.1-2ubuntu0.3"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.1-1ubuntu1","2.6.0-1","2.7.0-2","2.8.0-1","2.8.0-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.16.2-1","2.16.3-1","2.16.4-1ubuntu2","2.16.4-1ubuntu2+esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.16.9-0.1ubuntu1","2.16.11-0.1ubuntu1","2.16.11-0.3","2.28.0-1","2.28.0-1build1","2.28.0-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.28.3-1","2.28.6-1ubuntu1","2.28.7-1ubuntu1","2.28.7-1.1ubuntu1","2.28.8-1","2.28.8-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.6.2-3ubuntu1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.6.5-0.1ubuntu2","3.6.6-0.1ubuntu1","3.6.7-3ubuntu1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.6.2-3ubuntu1","3.6.5-0.1ubuntu1","3.6.5-0.1ubuntu2"]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.6.6-1.1"}]}],"bundled":10}],"products":[{"vendor":"trustedfirmware","product":"mbed_tls"}],"references":[{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories/","tags":["Vendor Advisory","advisory","report"]},{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-client-impersonation-while-resuming-tls13-session/","tags":["Vendor Advisory","advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34873","tags":["advisory"]},{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories"},{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-client-impersonation-while-resuming-tls13-session"},{"url":"https://github.com/advisories/GHSA-q24g-gcpv-7264"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34873.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-34873","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-34873","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-34873","tags":["report"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2026-25833","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-25834","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-25835","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-34871","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-34872","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-34873","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-34874","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-34875","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-34876","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-34877","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2026-34873","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","status":"published","published":"2026-04-01T00:00:00Z","modified":"2026-04-02T16:24:46.024Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"adp"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T14:20:13.962274Z"}],"euvd":[{"id":"EUVD-2026-18064","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","status":"published","published":"2026-04-01T00:00:00Z","modified":"2026-04-02T16:24:46Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T19:25:22.606516Z"}],"ghsa":[{"id":"GHSA-q24g-gcpv-7264","title":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while...","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","status":"published","published":"2026-04-01T21:30:32Z","modified":"2026-04-02T18:32:45Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T15:07:06.066601Z"}],"nvd":[{"id":"CVE-2026-34873","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","status":"published","published":"2026-04-01T21:17:01.99Z","modified":"2026-06-17T10:39:46.21Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"secondary"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T14:12:12.73929Z"}],"osv":[{"id":"CVE-2026-34873","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","status":"published","published":"2026-04-01T00:00:00Z","modified":"2026-10-28T02:31:13.169574858Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T15:45:02.673625Z"},{"id":"DEBIAN-CVE-2026-34873","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","status":"published","published":"2026-04-01T21:17:01.99Z","modified":"2026-10-01T03:03:10.675274506Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T15:45:54.587575Z"},{"id":"UBUNTU-CVE-2026-34873","description":"An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.","status":"published","published":"2026-04-01T21:17:00Z","modified":"2026-10-17T12:58:12.296706695Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T16:56:16.036833Z"},{"id":"openSUSE-SU-2026:10498-1","title":"libeverest-3.6.6-1.1 on GA media","description":"These are all security issues fixed in the libeverest-3.6.6-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-04-07T00:00:00Z","modified":"2026-04-08T07:50:16.855666Z","updated_at":"2026-11-02T16:58:38.415593Z"},{"id":"ROOT-OS-DEBIAN-12-CVE-2026-34873","title":"CVE-2026-34873 in mbedtls - Patched by Root","description":"Root has patched CVE-2026-34873 in the mbedtls package for Root:Debian:12. Multiple fixed versions available.","status":"published","published":"2026-08-25T12:15:34Z","modified":"2026-08-26T01:12:43.018927137Z","updated_at":"2026-11-02T15:53:32.037361Z"}]}}