Upstream information
Description
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.SUSE information
Overall state of this security issue: Does not affect SUSE products
This issue is currently rated as having moderate severity.
| CNA (MITRE) | |
|---|---|
| Base Score | 4.9 |
| Vector | CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N |
| Attack Vector | Physical |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | None |
| Scope | Changed |
| Confidentiality Impact | None |
| Integrity Impact | High |
| Availability Impact | None |
| CVSSv3 Version | 3.1 |
SUSE Timeline for this CVE
CVE page created: Fri Jul 4 18:00:55 2025CVE page last modified: Mon Jul 7 12:42:09 2025