CVE-2025-47917
Publication date 20 July 2025
Last updated 8 October 2025
Ubuntu priority
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).
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| mbedtls | 25.10 questing |
Vulnerable
|
| 25.04 plucky |
Vulnerable
|
|
| 24.04 LTS noble |
Vulnerable
|
|
| 22.04 LTS jammy |
Vulnerable
|
|
| 20.04 LTS focal |
Vulnerable
|
|
| 18.04 LTS bionic |
Vulnerable
|
|
| 16.04 LTS xenial |
Vulnerable
|
Notes
hlibk
The fix for the issue introduced a runtime error issue and a memory leak issue, which were fixed in subsequent commits (listed in the patches).
Patch details
| Package | Patch details |
|---|---|
| mbedtls |
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
8.9 · High
|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Changed |
| Confidentiality | Low |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H |