CVE-2026-34872

Name: CVE-2026-34872
Creator: NVD / NIST
Published: 2026-04-01T20:16:27.493+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 0.20%

Last modified Jun 17, 2026

CVE-2026-34872 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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. EPSS estimates a 0.20% chance of exploitation in the next 30 days.

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).

Metrics

CVSS 3.1

9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

0.20%

10.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-347

Affected Software

Vendor	Product	Versions
Arm	Mbed Tls	< 3.6.6
Arm	Tf-Psa-Crypto	1.0.0

References

https://mbed-tls.readthedocs.io/en/latest/security-advisories/Vendor Advisory
https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-ffdh-peerkey-checks/Mitigation, Vendor Advisory

Timeline

Published: Apr 1, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-34872?

How severe is CVE-2026-34872?

CVE-2026-34872 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-34872?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34872?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST