CVE-2026-34872 Affecting mbedtls package, versions <3.6.6-0.1
Threat Intelligence
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The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-MBEDTLS-15918577
- published6 Apr 2026
- disclosed1 Apr 2026
Introduced: 1 Apr 2026
CVE-2026-34872 (opens in a new tab)How to fix?
Upgrade Debian:unstable mbedtls to version 3.6.6-0.1 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 Debian.
See How to fix? for Debian:unstable 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).