# CVE-2023-39975: Use after free in n/a

> An authenticated user can trigger a double free in MIT Kerberos, potentially causing a denial of service or arbitrary code execution.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Aug 2023
- **Updated:** 25 Feb 2026
- **Also known as:** CLSA-2024-1718787475, GHSA-4grv-wgvh-8x82, openSUSE-SU-2024:13527-1

## What is CVE-2023-39975?

CVE-2023-39975 is a high-severity use after free vulnerability in Mit Kerberos 5, published on 16 Aug 2023. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

kdc/do_tgs_req.c in MIT Kerberos 5 (aka krb5) 1.21 before 1.21.2 has a double free that is reachable if an authenticated user can trigger an authorization-data handling failure. Incorrect data is copied from one ticket to another.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2023-39975?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `krb5` | openSUSE:Tumbleweed | All versions | 1.21.2-1.1 |

Products: Mit Kerberos 5.

## How do I fix CVE-2023-39975?

Upgrade to a fixed version.

## Is CVE-2023-39975 being exploited?

There is no known exploitation of CVE-2023-39975 in the wild and no public exploit code.

## Other vulnerabilities in Mit Kerberos 5

- [CVE-2011-0285](https://insights.sbomify.com/CVE-2011-0285/): Use after free in n/a (critical 10.0)
- [CVE-2008-0947](https://insights.sbomify.com/CVE-2008-0947/): Memory corruption in n/a (critical 10.0)
- [CVE-2007-5902](https://insights.sbomify.com/CVE-2007-5902/): Integer overflow in n/a (critical 10.0)
- [CVE-2007-4743](https://insights.sbomify.com/CVE-2007-4743/): Memory corruption in n/a (critical 10.0)
- [CVE-2007-3999](https://insights.sbomify.com/CVE-2007-3999/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-39975 and fix it if it is affected.

What it is: CVE-2023-39975 is a high-severity use after free vulnerability in Mit Kerberos 5, published on 16 Aug 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-39975 in the wild and no public exploit code.

Affected product: Mit Kerberos 5. 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-2023-39975/ (Markdown: https://insights.sbomify.com/CVE-2023-39975/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-39975
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-39975
- OSV: https://osv.dev/vulnerability/CVE-2023-39975

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-39975/
Summaries are generated and may contain mistakes; the official description above is the record.