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Vulnerability · Published Jul 20, 2025 · Assigned by mitre

CVE-2025-47917

High 8.9

In plain English

A high-severity use-after-free in mbedtls from Mbed. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.4% (higher than 84% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.9High
Exploit odds (30 days)2.4%top 15.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC

Official 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).

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20mbedtls3.6.4-r0ALPINE-CVE-2025-47917
Alpine:v3.21mbedtls3.6.4-r0ALPINE-CVE-2025-47917
Alpine:v3.22mbedtls3.6.4-r0ALPINE-CVE-2025-47917
Alpine:v3.23mbedtls3.6.4-r0ALPINE-CVE-2025-47917
Alpine:v3.24mbedtls3.6.4-r0ALPINE-CVE-2025-47917
Alpine:v3.24mbedtls33.6.4-r0ALPINE-CVE-2025-47917
Debian:12mbedtlsno fix listedDEBIAN-CVE-2025-47917
Debian:13mbedtls3.6.4-1DEBIAN-CVE-2025-47917
Debian:14mbedtls3.6.4-1DEBIAN-CVE-2025-47917
Ubuntu:25.10mbedtlsno fix listedUBUNTU-CVE-2025-47917

Affected products (as reported)

VendorProductVersions
Mbed mbedtls 0 – before 3.6.4

Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H

References