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).

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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). (CVE-2026-34872)

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the d77bd2f5-34f0-11f1-bc6d-3c7c3fba4204 advisory.

    https://mbed-tls.readthedocs.io/en/latest/security-advisories/ reports:

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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). (CVE-2026-34872)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
459138	Echo: mbedtls: security update to 3.6.6	Tenable Cloud Security	Echo Local Security Checks	Local	critical
459138	Echo: mbedtls: security update to 3.6.6	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	critical
305996	FreeBSD : Mbed TLS -- vulnerabilities (d77bd2f5-34f0-11f1-bc6d-3c7c3fba4204)	Nessus	FreeBSD Local Security Checks	Local	critical
304714	Linux Distros Unpatched Vulnerability : CVE-2026-34872	Nessus	Misc.	Local	critical

Detections

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CVE-2026-34872

critical

Tenable Plugins

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