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🛡️ CVE-2025-49600 — mbed-tls

🟡 CVSS 4.9 — Medium ✅ No Known Exploit CWE-325 NVD
4.9
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached with physical access to the device, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality none, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N

  • Attack vector: Physical — the attacker has to touch the device.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: None.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2025-49600 is classified as CWE-325: Missing Cryptographic Step. A required step of a cryptographic algorithm is skipped, weakening the guarantees it should provide.

Affected software

CVE-2025-49600 is recorded against 1 package.

  • mbed-tls (from 3.3.0 up to 3.6.4)

Timeline and source

Published on 4 July 2025 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com

Other advisories for this package

mbed-tls has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-325: Missing Cryptographic Step) in other software:

CVE-2025-49600 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity MEDIUM
CVSS Score 4.9
CVSS Vector CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
CWE CWE-325
Public Exploit ✅ No
Source NVD
Published 2025-07-04
Updated 2026-08-20
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
mbed-tls 3.3.0 3.6.4

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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