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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.002 (11.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- Trustedfirmware Mbed TLS — versions 4.0.0
Weakness classification (CWE)
References
- mbed-tls.readthedocs.io/en/latest/security-advisories/ (Vendor Advisory)
- mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory… (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.