Out-of-bounds read in mbedtls
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
In MbedTLS 3.3.0 before 3.6.4, mbedtls_lms_import_public_key does not check that the input buffer is at least 4 bytes before reading a 32-bit field, allowing a possible out-of-bounds read on truncated input. Specifically, an out-of-bounds read in mbedtls_lms_import_public_key allows context-dependent attackers to trigger a crash or limited adjacent-memory disclosure by supplying a truncated LMS (Leighton-Micali Signature) public-key buffer under four bytes. An LMS public key starts with a 4-byte type indicator. The function mbedtls_lms_import_public_key reads this type indicator before validating the size of its input.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA mbedtls (Mbed) Fixed in 3.6.4
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Mbed mbedtls 3.6.4
4 records Highest priority Priority HIGH 1 HIGH, 3 LOW
Other records, highest priority first
- TI-2025-32620 Mbed TLS before 3.6.4 has a race condition in AESNI detection if certain compiler…Priority HIGH 69
- TI-2025-32621 Mbed TLS before 3.6.4 has a PEM parsing one-byte heap-based buffer underflow, in…Priority LOW 22
- TI-2025-31613 In MbedTLS 3.3.0 before 3.6.4, mbedtls_lms_verify may accept invalid signatures if hash…Priority LOW 22
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2025-49601
- 2026-10-03 Alias added: GHSA-h9v9-9rwj-pmq9
References
More Mbed vulnerabilities
- TI-2025-32620 Mbed TLS before 3.6.4 has a race condition in AESNI detection if certain compiler… CVSS 3.1HIGH 7.8
- TI-2025-30320 Use after free in mbedtls CVSS 3.1CRITICAL 9.8
- TI-2019-12830 Buffer overflows were discovered in the CoAP library in Arm Mbed OS 5.14.0. CVSS 3.1CRITICAL 9.8
- TI-2019-12829 An integer overflow was discovered in the CoAP library in Arm Mbed OS 5.14.0. CVSS 3.1CRITICAL 9.8
- TI-2025-31103 NULL pointer dereference in mbedtls CVSS 3.1HIGH 7.5
- TI-2025-20584 Use of uninitialized resource in mbedtls CVSS 3.1MEDIUM 5.4
Sources
- CVE-2025-49601 · CVE Program
- CVE-2025-49601 · NVD
- FIRST EPSS
- GHSA-h9v9-9rwj-pmq9 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-49601 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences