CVE-2026-34872: 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).

Overview

Severity
High (CVSS 7.5)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U
Exploit Status
Not Exploited
Patch Tuesday
2026-Apr
Released
2026-05-07
Last Updated
2026-06-02
EPSS Score
0.20% (percentile: 10.4%)

Affected Products (2)

Open Source Software

  • azl3 nodejs24 24.14.1-2 on Azure Linux 3.0

Other

  • 21370-17084

Revision History

  • 2026-05-07: Information published.
  • 2026-05-19: Information published.
  • 2026-05-31: Information published.
  • 2026-06-01: Information published.
  • 2026-06-02: Information published.