CVE-2025-27809 Security feature bypass in mbedtls
Mbed TLS clients may accept trusted certificates for arbitrary hostnames if hostname verification is not explicitly enabled, bypassing TLS security checks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-27809?
CVE-2025-27809 is a medium-severity vulnerability in Arm Mbed Tls, published on 25 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Mbed TLS before 2.28.10 and 3.x before 3.6.3, on the client side, accepts servers that have trusted certificates for arbitrary hostnames unless the TLS client application calls mbedtls_ssl_set_hostname.
Weakness: CWE-1188
Which versions are affected by CVE-2025-27809?
It affects 2 products.
Products include Arm Mbed Tls, Trustedfirmware Mbed Tls.
How do I fix CVE-2025-27809?
Upgrade to a fixed version.
Is CVE-2025-27809 being exploited?
There is no known exploitation of CVE-2025-27809 in the wild and no public exploit code.
Other vulnerabilities in Arm Mbed Tls
Sources
Also known as ALPINE-CVE-2025-27809, DEBIAN-CVE-2025-27809, GHSA-76fv-m4gp-q47j, JLSEC-2025-227, ROOT-OS-DEBIAN-12-CVE-2025-27809, UBUNTU-CVE-2025-27809.