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. 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).
Overview
- Severity
- High (CVSS 8.9)
- CVSS Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H
- Exploit Status
- Not Exploited
- Patch Tuesday
- 2025-Jul
- Released
- 2026-09-03
- EPSS Score
- 2.06% (percentile: 80.1%)
Detection & Weaponization (1 sources)
Maturity: Exploit
- GitHub PoC: 1 repositories
Affected Products (1)
Other
Security Updates (1)
Revision History
- 2026-09-03: Information published.