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).

CriticalVendor CVSS 9.1 / 10 1 CVE Published May 7, 2026 at 1:13 AM UTC

Summary

Mariner

Release Notes

May 7, 2026 at 1:13 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Nov 12, 2026 at 5:33 PM UTC
Updated by Microsoft Security Response Center
The vendor changed the advisory after it was first published.
Nov 13, 2026 at 9:05 AM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Nov 13, 2026 at 3:10 PM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Details collected from Microsoft Security Response Center.

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