{"cve":"CVE-2026-34872","nvd":{"published":"2026-04-01T20:16:27.493","modified":"2026-06-17T10:39:46.057","status":"Analyzed","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).","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-347"],"references":["https://mbed-tls.readthedocs.io/en/latest/security-advisories/","https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-ffdh-peerkey-checks/"],"products":["arm:mbed_tls","arm:tf-psa-crypto"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-34872","score":0.00208,"percentile":0.1094,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}