CVE-2026-34872 Affecting mbedtls package, versions <3.6.6


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.28% (18th percentile)

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  • Snyk IDSNYK-ECHOLATEST-MBEDTLS-18169653
  • published22 Jul 2026
  • disclosed1 Apr 2026

Introduced: 1 Apr 2026

CVE-2026-34872  (opens in a new tab)

How to fix?

Upgrade Echo:latest mbedtls to version 3.6.6 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream mbedtls package and not the mbedtls package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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).