# CVE-2025-49600

## Summary

- **CVE ID:** CVE-2025-49600
- **Severity:** MEDIUM
- **CVSS Score:** 4.9 (CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N)
- **CWE:** CWE-325
- **Published:** Jul 4, 2025
- **Last Modified:** Mar 13, 2026

## 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.

## Affected Products

- Mbed — mbedtls (3.3.0)

## References

- [CNA](https://github.com/Mbed-TLS/mbedtls-docs/blob/main/security-advisories/mbedtls-security-advisory-2025-06-3.md)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.13%
- **EPSS Percentile:** 3.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._