{"id":"CVE-2025-49600","details":"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.","modified":"2026-04-10T05:29:00.492303Z","published":"2025-07-04T15:15:22.277Z","references":[{"type":"ADVISORY","url":"https://github.com/Mbed-TLS/mbedtls-docs/blob/main/security-advisories/mbedtls-security-advisory-2025-06-3.md"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/armmbed/mbedtls","events":[{"introduced":"8c89224991adff88d53cd380f42a2baa36f91454"},{"fixed":"c765c831e5c2a0971410692f92f7a81d6ec65ec2"}],"database_specific":{"versions":[{"introduced":"3.3.0"},{"fixed":"3.6.4"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-49600.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N"}]}