Vulnerability Details CVE-2025-49600
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 0.9%
CVSS Severity
CVSS v3 Score 4.9
Products affected by CVE-2025-49600
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cpe:2.3:a:arm:mbed_tls:3.3.0
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cpe:2.3:a:arm:mbed_tls:3.4.0
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cpe:2.3:a:arm:mbed_tls:3.4.1
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cpe:2.3:a:arm:mbed_tls:3.5.0
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cpe:2.3:a:arm:mbed_tls:3.5.1
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cpe:2.3:a:arm:mbed_tls:3.5.2
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cpe:2.3:a:arm:mbed_tls:3.6.0
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cpe:2.3:a:arm:mbed_tls:3.6.1
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cpe:2.3:a:arm:mbed_tls:3.6.2
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cpe:2.3:a:arm:mbed_tls:3.6.3