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).
Published: 2026-04-01
Score: 9.1 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories

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History

Wed, 01 Apr 2026 23:45:00 +0000

Type Values Removed Values Added
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).
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-04-01T19:52:25.548Z

Reserved: 2026-03-31T00:00:00.000Z

Link: CVE-2026-34872

cve-icon Vulnrichment

Updated: 2026-04-01T19:50:04.483Z

cve-icon NVD

Status : Received

Published: 2026-04-01T20:16:27.493

Modified: 2026-04-01T20:16:27.493

Link: CVE-2026-34872

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses