What is CVE-2026-25834?

CVE-2026-25834 is a medium-severity vulnerability in Trustedfirmware Mbed_tls, classified under Improper Certificate Validation. CVSS score: 6.5/10. Published 2026-04-01.

How severe is CVE-2026-25834?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Trustedfirmware Mbed_tls

CVE-2026-25834

Mbed TLS v3.3.0 up to 3.6.5 and 4.0.0 allows Algorithm Downgrade.

Vulnerability class: Improper Certificate Validation

EPSS: 0.000 (6.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L.

Affected products

Trustedfirmware Mbed_tls — versions 4.0.0
N/a — versions n/a

Weakness classification (CWE)

CWE-295 — Improper Certificate Validation
CWE-327 — Use of a Broken or Risky Cryptographic Algorithm

References

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

Frequently asked questions

What is CVE-2026-25834?: CVE-2026-25834 is a medium-severity vulnerability in Trustedfirmware Mbed_tls, classified under Improper Certificate Validation. CVSS score: 6.5/10. Published 2026-04-01.
How severe is CVE-2026-25834?: Medium severity. CVSS v3 base score is 6.5 out of 10.