# CVE-2021-44758: Null dereference in n/a

> Attackers can cause a denial of service in Heimdal via a NULL pointer dereference in the SPNEGO acceptor mechanism.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 26 Dec 2022
- **Updated:** 14 Apr 2025
- **Also known as:** ALPINE-CVE-2021-44758, AZL-44859, CLEANSTART-2024-UF28552, DEBIAN-CVE-2021-44758, GHSA-69h9-669w-88xv, UBUNTU-CVE-2021-44758

## What is CVE-2021-44758?

CVE-2021-44758 is a high-severity vulnerability in n/a, published on 26 Dec 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Heimdal before 7.7.1 allows attackers to cause a NULL pointer dereference in a SPNEGO acceptor via a preferred_mech_type of GSS_C_NO_OID and a nonzero initial_response value to send_accept.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2021-44758?

It affects 1 product.


Products: Heimdal Project Heimdal.

## How do I fix CVE-2021-44758?

Upgrade to a fixed version.

## Is CVE-2021-44758 being exploited?

There is no known exploitation of CVE-2021-44758 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2022-44640](https://insights.sbomify.com/CVE-2022-44640/): Use after free in n/a (critical 9.8)
- [CVE-2022-42898](https://insights.sbomify.com/CVE-2022-42898/): Integer overflow in n/a (high 8.8)
- [CVE-2022-3116](https://insights.sbomify.com/CVE-2022-3116/): Null dereference in Heimdal Software Kerberos (high 7.5)
- [CVE-2022-45142](https://insights.sbomify.com/CVE-2022-45142/): Security feature bypass in Samba (high 7.5)
- [CVE-2018-16860](https://insights.sbomify.com/CVE-2018-16860/): Auth bypass in samba (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-44758 and fix it if it is affected.

What it is: CVE-2021-44758 is a high-severity vulnerability in n/a, published on 26 Dec 2022. 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-2021-44758 in the wild and no public exploit code.

Affected product: n/a. 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-2021-44758/ (Markdown: https://insights.sbomify.com/CVE-2021-44758/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-44758
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-44758
- OSV: https://osv.dev/vulnerability/CVE-2021-44758

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-44758/
Summaries are generated and may contain mistakes; the official description above is the record.