CVE-2025-27810: Mbed TLS: Uninitialized Data in TLS Messages Can Bypass Authentication

Summary

An issue in some versions of Mbed TLS can cause authentication to be bypassed. This is because the software uses memory that hasn't been properly cleaned up, potentially allowing hackers to intercept and reuse secure messages. To stay secure, update to the latest version of Mbed TLS, version 2.28.10 or 3.6.3 and later.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software

Vendor	Product	Affected versions
arm	mbed_tls	< 2.28.10 >= 3.0.0, < 3.6.3 `cpe:2.3:a:arm:mbed_tls::::::::`

Original title

Mbed TLS before 2.28.10 and 3.x before 3.6.3, in some cases of failed memory allocation or hardware errors, uses uninitialized stack memory to compose the TLS Finished message, potentially leading ...

Original description

Mbed TLS before 2.28.10 and 3.x before 3.6.3, in some cases of failed memory allocation or hardware errors, uses uninitialized stack memory to compose the TLS Finished message, potentially leading to authentication bypasses such as replays.

nvd CVSS3.1 4.8

Vulnerability type

CWE-908 Use of Uninitialized Resource

https://github.com/Mbed-TLS/mbedtls/releases Release Notes
https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-a... Vendor Advisory