{"id":"CVE-2026-34872","aliases":["DEBIAN-CVE-2026-34872","EUVD-2026-18021","GHSA-347r-37hj-5jc9","JLSEC-2026-466","ROOT-OS-DEBIAN-12-CVE-2026-34872","UBUNTU-CVE-2026-34872","openSUSE-SU-2026:10498-1"],"status":"published","title":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is...","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","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":"2026-11-11","score":0.00208,"percentile":0.11028,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-347"],"published":"2026-04-01T00:00:00Z","modified":"2026-10-28T02:30:57Z","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.15","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.15","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":"Julia","package":"MbedTLS_jll","ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}]},{"source":"osv","ecosystem":"Root:Debian:12","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.28.3-1.root.io.15"},{"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.15"},{"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":"arm","product":"mbed_tls"},{"vendor":"arm","product":"tf-psa-crypto"}],"references":[{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories/","tags":["Vendor Advisory","advisory","web","report"]},{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-ffdh-peerkey-checks/","tags":["Mitigation","Vendor Advisory","advisory","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34872","tags":["advisory","web"]},{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories","tags":["web"]},{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-ffdh-peerkey-checks","tags":["web"]},{"url":"https://github.com/advisories/GHSA-347r-37hj-5jc9","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34872.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-34872","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-34872","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-34872","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-2026-34872","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-04-01T00:00:00Z","modified":"2026-04-01T19:52:25.548Z","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-347"],"updated_at":"2026-11-02T14:20:14.302133Z"}],"euvd":[{"id":"EUVD-2026-18021","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-04-01T00:00:00Z","modified":"2026-04-01T19:52:25Z","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":"2026-11-02T19:25:23.620594Z"}],"ghsa":[{"id":"GHSA-347r-37hj-5jc9","title":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is...","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-04-01T21:30:31Z","modified":"2026-04-01T21:30:38Z","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-347"],"updated_at":"2026-11-02T15:07:04.885246Z"}],"nvd":[{"id":"CVE-2026-34872","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-04-01T20:16:27.493Z","modified":"2026-06-17T10:39:46.057Z","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-347"],"updated_at":"2026-11-02T14:12:12.73929Z"}],"osv":[{"id":"CVE-2026-34872","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-04-01T00:00:00Z","modified":"2026-10-28T02:30:57.204582534Z","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-2026-34872","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-04-01T20:16:27.493Z","modified":"2026-10-01T03:03:03.978056685Z","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":"JLSEC-2026-466","title":"Mbed TLS peer can force the FFDH shared secret into a small set of values","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-05-07T16:17:33.752Z","modified":"2026-07-18T00:02:04.332598906Z","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":"2026-11-02T15:47:18.573531Z"},{"id":"ROOT-OS-DEBIAN-12-CVE-2026-34872","title":"CVE-2026-34872 in mbedtls - Patched by Root","description":"Root has patched CVE-2026-34872 in the mbedtls package for Root:Debian:12. Multiple fixed versions available.","status":"published","published":"2026-08-25T12:15:34Z","modified":"2026-08-26T01:12:43.780094785Z","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":"2026-11-02T15:53:32.037361Z"},{"id":"UBUNTU-CVE-2026-34872","description":"An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).","status":"published","published":"2026-04-01T20:16:00Z","modified":"2026-10-17T12:58:12.287471774Z","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"}]}}