CVE-2025-47917
Mbed TLS before 3.6.4 allows a use-after-free in certain situations of applications that are developed in accordance with the documentation.
Public exploit code
Working exploit or proof of concept code has been published for this vulnerability. Treat unpatched systems as at risk.
- Mbed TLS 3.6.4 - Use-After-Free2025-09-16 · local · multiple
Impact
Mbed TLS before 3.6.4 allows a use-after-free in certain situations of applications that are developed in accordance with the documentation. The function mbedtls_x509_string_to_names() takes a head argument that is documented as an output argument. The documentation does not suggest that the function will free that pointer; however, the function does call mbedtls_asn1_free_named_data_list() on that argument, which performs a deep free(). As a result, application code that uses this function (relying only on documented behavior) is likely to still hold pointers to the memory blocks that were freed, resulting in a high risk of use-after-free or double-free. In particular, the two sample programs x509/cert_write and x509/cert_req are affected (use-after-free if the san string contains more than one DN).
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Arm | Mbed Tls | before 3.6.4 |
Weakness classification
References
- NVD record
- CVE.org record
- https://github.com/Mbed-TLS/mbedtls-docs/blob/main/security-advisories/mbedtls-security-advisory-2025-06-7.md
- https://mbed-tls.readthedocs.io/en/latest/tech-updates/security-advisories/
- https://lists.debian.org/debian-lts-announce/2025/08/msg00013.html
- https://lists.debian.org/debian-lts-announce/2025/08/msg00025.html