# CVE-2021-3445: Code injection in libdnf

> Attackers can execute arbitrary code by altering RPM package headers and tricking users into installing them via libdnf.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** ALSA-2021:4464, CLSA-2022-1646666491, CLSA-2022-1646666523, CLSA-2026-1779434064, DEBIAN-CVE-2021-3445, GHSA-jrcf-96j2-jpvh, OESA-2021-1224, RHSA-2021:4464, RLSA-2021:4464, UBUNTU-CVE-2021-3445, openSUSE-SU-2024:10934-1

## What is CVE-2021-3445?

CVE-2021-3445 is a high-severity code injection vulnerability in Fedoraproject Fedora, published on 19 May 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A flaw was found in libdnf's signature verification functionality in versions before 0.60.1. This flaw allows an attacker to achieve code execution if they can alter the header information of an RPM package and then trick a user or system into installing it. The highest risk of this vulnerability is to confidentiality, integrity, as well as system availability.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2021-3445?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libdnf-devel` | AlmaLinux:8 | All versions | 0.63.0-3.el8 |
| `dnf` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.7.0-4.el8 |
| `dnf-automatic` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.7.0-4.el8 |
| `dnf-data` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.7.0-4.el8 |
| `dnf-plugins-core` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.0.21-3.el8 |
| `libdnf` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.63.0-3.el8 |
| `libdnf-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.63.0-3.el8 |
| `libdnf-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.63.0-3.el8 |
| `python3-dnf` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.7.0-4.el8 |
| `python3-dnf-plugin-post-transaction-actions` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.0.21-3.el8 |
| `python3-dnf-plugin-versionlock` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.0.21-3.el8 |
| `python3-dnf-plugins-core` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.0.21-3.el8 |
| `python3-hawkey` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.63.0-3.el8 |
| `python3-hawkey-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.63.0-3.el8 |
| `python3-libdnf` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.63.0-3.el8 |
| `python3-libdnf-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.63.0-3.el8 |
| `yum` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.7.0-4.el8 |
| `yum-utils` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.0.21-3.el8 |
| `libdnf-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:0.63.0-3.el8 |
| `libdnf-debugsource` | Red Hat:enterprise_linux:8::crb | All versions | 0:0.63.0-3.el8 |
| `libdnf-devel` | Red Hat:enterprise_linux:8::crb | All versions | 0:0.63.0-3.el8 |
| `python3-hawkey-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:0.63.0-3.el8 |
| `python3-libdnf-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:0.63.0-3.el8 |
| `dnf` | Rocky Linux:8 | All versions | 0:4.7.0-4.el8 |
| `dnf-plugins-core` | Rocky Linux:8 | All versions | 0:4.0.21-3.el8 |
| `libdnf` | Rocky Linux:8 | All versions | 0:0.63.0-3.el8 |

Products: Fedoraproject Fedora, Redhat Enterprise Linux, Rpm Libdnf.

## How do I fix CVE-2021-3445?

Upgrade to a fixed version.

## Is CVE-2021-3445 being exploited?

There is no known exploitation of CVE-2021-3445 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3445 and fix it if it is affected.

What it is: CVE-2021-3445 is a high-severity code injection vulnerability in Fedoraproject Fedora, published on 19 May 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-3445 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2021-3445/ (Markdown: https://insights.sbomify.com/CVE-2021-3445/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3445
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3445
- OSV: https://osv.dev/vulnerability/CVE-2021-3445

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3445/
Summaries are generated and may contain mistakes; the official description above is the record.