CVE-2025-47917 EXPLOIT
Patch early
A public exploit exists.
Description
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).
Scoring
| CVSS | 8.9 (HIGH, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H |
| EPSS | 2.28% — more likely to be exploited than 83% of all CVEs |
| Weakness | CWE-416 |
| On CISA KEV | no |
| Public exploit | yes |
| Published | 2025-07-20 |
| Last modified | 2026-06-17 |
Affected (1)
| Vendor | Product |
|---|---|
| arm | mbed tls |
Public exploits
| Source | Title | Date |
|---|---|---|
| exploit-db | Mbed TLS 3.6.4 - Use-After-Free | 2025-09-16 |
References
- 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
→ the Explorer · watch your stack · NVD