# CVE-2025-47917: Use after free in mbedtls

> A use-after-free vulnerability in Mbed TLS allows attackers to potentially execute code or cause denial of service via crafted X.509 certificates.

- **Severity:** High 8.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Jul 2025
- **Updated:** 3 Nov 2025
- **Also known as:** ALPINE-CVE-2025-47917, DEBIAN-CVE-2025-47917, DLA-4274-2, GHSA-7xcg-xp2h-m42v, JLSEC-2025-231, ROOT-OS-DEBIAN-12-CVE-2025-47917, UBUNTU-CVE-2025-47917

## What is CVE-2025-47917?

CVE-2025-47917 is a high-severity use after free vulnerability in Arm Mbed Tls, published on 20 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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).

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-47917?

It affects 1 product.


Products: Arm Mbed Tls.

## How do I fix CVE-2025-47917?

Upgrade to a fixed version.

## Is CVE-2025-47917 being exploited?

There is no known exploitation of CVE-2025-47917 in the wild and no public exploit code.

Public exploit code:

- PoC exploit for CVE-2025-47917: Use-After-Free in mbedTLS leading to remote code execution. (github_poc): https://github.com/byteReaper77/CVE-2025-47917
- Mbed TLS 3.6.4 - Use-After-Free (exploitdb)

## Other vulnerabilities in Arm Mbed Tls

- [CVE-2026-34877](https://insights.sbomify.com/CVE-2026-34877/): Deserialization in n/a (critical 9.8)
- [CVE-2022-46393](https://insights.sbomify.com/CVE-2022-46393/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-44732](https://insights.sbomify.com/CVE-2021-44732/): Use after free in n/a (critical 9.8)
- [CVE-2017-18187](https://insights.sbomify.com/CVE-2017-18187/): Integer overflow in n/a (critical 9.8)
- [CVE-2018-0487](https://insights.sbomify.com/CVE-2018-0487/): Memory corruption in ARM mbed TLS before 1.3.22, before 2.1.10, and before 2.7.0 (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-47917 and fix it if it is affected.

What it is: CVE-2025-47917 is a high-severity use after free vulnerability in Arm Mbed Tls, published on 20 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-47917 in the wild and no public exploit code.

Affected product: Arm Mbed Tls. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-47917/ (Markdown: https://insights.sbomify.com/CVE-2025-47917/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-47917
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-47917
- OSV: https://osv.dev/vulnerability/CVE-2025-47917

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-47917/
Summaries are generated and may contain mistakes; the official description above is the record.