CVE intelligence

CVE-2025-47917

Vulnerability intelligence

Published Jul 20, 2025Sources checked Nov 11, 2026

9.8CRITICALCVSS out of 10

What this means

Review the available evidence

CVE-2025-47917 and is rated Critical severity with a CVSS score of 9.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

Public exploit: Cataloged public exploit.

Exploit-DB: Mbed TLS 3.6.4 - Use-After-Free (2026-09-23 21:40:27.335989+00)
Exploit-DB lists a public exploit or proof of concept for this CVE. SecurityAlert has not executed it; this is not evidence of attacks against your systems.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Sep 3, 2026

See the Microsoft Security Update Guide for the update that applies to your product.

CISA KEVNot listedBased on the latest collected catalog

EPSS2.4%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is 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).

Source: NVD