CVE-2025-47917

What it is

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).

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data tampering, service disruption.

Exploit odds

2.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-07-20 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 09:28 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.4% in the next 30 days (EPSS).
• Severity: 8.9 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-07-20 19:15 UTC

Last modified

2026-06-17 09:28 UTC

Exploit probability

2.4% · EPSS, next 30 days

Weakness

CWE-416 · Use after free

Record status

Modified

Affected

• Arm Mbed Tls < 3.6.4

Attack profile CVSS 3.1 · 8.9

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

Low

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-47917.md and follow it. Check whether this project is affected by CVE-2025-47917. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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