Source: mbedtls
Version: 3.6.3-1
Severity: important
Tags: security upstream
X-Debbugs-Cc: [email protected], Debian Security Team <[email protected]>

Hi,

The following vulnerability was published for mbedtls.

CVE-2025-49600[0]:
| In MbedTLS 3.3.0 before 3.6.4, mbedtls_lms_verify may accept invalid
| signatures if hash computation fails and internal errors go
| unchecked, enabling LMS (Leighton-Micali Signature) forgery in a
| fault scenario. Specifically, unchecked return values in
| mbedtls_lms_verify allow an attacker (who can induce a hardware hash
| accelerator fault) to bypass LMS signature verification by reusing
| stale stack data, resulting in acceptance of an invalid signature.
| In mbedtls_lms_verify, the return values of the internal Merkle tree
| functions create_merkle_leaf_value and create_merkle_internal_value
| are not checked. These functions return an integer that indicates
| whether the call succeeded or not. If a failure occurs, the output
| buffer (Tc_candidate_root_node) may remain uninitialized, and the
| result of the signature verification is unpredictable. When the
| software implementation of SHA-256 is used, these functions will not
| fail. However, with hardware-accelerated hashing, an attacker could
| use fault injection against the accelerator to bypass verification.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2025-49600
https://www.cve.org/CVERecord?id=CVE-2025-49600
[1] https://github.com/Mbed-TLS/mbedtls-docs/blob/main/security-advisories/mbedtls-security-advisory-2025-06-3.md

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)