# CVE-2021-46705: grub2-once uses fixed file name in /var/tmp

> Local attackers can truncate arbitrary files via insecure temporary file handling in grub2-once, requiring a patch to mitigate.

- **Severity:** Medium 5.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Mar 2022
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-p6fp-whjx-7g5m, openSUSE-SU-2024:11926-1

## What is CVE-2021-46705?

CVE-2021-46705 is a medium-severity vulnerability in SUSE Linux Enterprise Server 15 SP4, published on 16 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Insecure Temporary File vulnerability in grub-once of grub2 in SUSE Linux Enterprise Server 15 SP4, openSUSE Factory allows local attackers to truncate arbitrary files. This issue affects: SUSE Linux Enterprise Server 15 SP4 grub2 versions prior to 2.06-150400.7.1. SUSE openSUSE Factory grub2 versions prior to 2.06-18.1.

Weakness: CWE-377 (DEPRECATED: Insecure Temporary File)

## Which versions are affected by CVE-2021-46705?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `grub2` | openSUSE:Tumbleweed | All versions | 2.06-18.1 |

Products: Gnu Grub2.

## How do I fix CVE-2021-46705?

Apply the vendor's patch.

## Is CVE-2021-46705 being exploited?

There is no known exploitation of CVE-2021-46705 in the wild and no public exploit code.

## Other vulnerabilities in SUSE Linux Enterprise Server 15 SP4

- [CVE-2024-56737](https://insights.sbomify.com/CVE-2024-56737/): Memory corruption in GRUB2 (high 8.8)
- [CVE-2022-28733](https://insights.sbomify.com/CVE-2022-28733/): Integer underflow in grub_net_recv_ip4_packets (high 8.1)
- [CVE-2022-28734](https://insights.sbomify.com/CVE-2022-28734/): Out-of-bounds write when handling split HTTP headers (high 8.1)
- [CVE-2025-61662](https://insights.sbomify.com/CVE-2025-61662/): Grub2: missing unregister call for gettext command may lead to use-after-free (high 7.8)
- [CVE-2024-45782](https://insights.sbomify.com/CVE-2024-45782/): Grub2: fs/hfs: strcpy() using the volume name (fs/hfs.c:382) (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-46705 and fix it if it is affected.

What it is: CVE-2021-46705 is a medium-severity vulnerability in SUSE Linux Enterprise Server 15 SP4, published on 16 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-46705 in the wild and no public exploit code.

Affected product: SUSE Linux Enterprise Server 15 SP4. 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-2021-46705/ (Markdown: https://insights.sbomify.com/CVE-2021-46705/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-46705
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-46705
- OSV: https://osv.dev/vulnerability/CVE-2021-46705

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-46705/
Summaries are generated and may contain mistakes; the official description above is the record.