What is CVE-2026-34872?

CVE-2026-34872 is a critical-severity vulnerability in Arm Mbed_tls, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2026-04-01.

How severe is CVE-2026-34872?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Arm Mbed_tls

CVE-2026-34872

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 sh…

EPSS: 0.002 (10.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Arm Mbed_tls
Arm Tf-psa-crypto — versions 1.0.0
N/a — versions n/a

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

References

cve@mitre.org (Vendor Advisory)
cve@mitre.org (Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-34872?: CVE-2026-34872 is a critical-severity vulnerability in Arm Mbed_tls, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2026-04-01.
How severe is CVE-2026-34872?: Critical severity. CVSS v3 base score is 9.1 out of 10.