# CVE-2021-3621: Command injection in sssd

> Attackers can trick root users into running crafted sssctl commands to execute arbitrary shell commands and gain root privileges.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/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:** 23 Dec 2021
- **Updated:** 3 Nov 2025
- **Also known as:** ALSA-2021:3151, DEBIAN-CVE-2021-3621, DLA-2758-1, GHSA-g527-g4q2-57xc, MGASA-2021-0502, OESA-2021-1340, RHSA-2021:3151, RHSA-2021:3178, RHSA-2021:3336, RHSA-2021:3365, RLSA-2021:3151, SUSE-RU-2021:3185-1, SUSE-SU-2021:2873-1, SUSE-SU-2021:2941-1, SUSE-SU-2022:0826-1, SUSE-SU-2022:1258-1, SUSE-SU-2022:2763-1, UBUNTU-CVE-2021-3621, openSUSE-SU-2021:2941-1

## What is CVE-2021-3621?

CVE-2021-3621 is a high-severity command injection vulnerability in Fedoraproject Fedora, published on 23 Dec 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 SSSD, where the sssctl command was vulnerable to shell command injection via the logs-fetch and cache-expire subcommands. This flaw allows an attacker to trick the root user into running a specially crafted sssctl command, such as via sudo, to gain root access. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-77 (Improper Neutralization of Special Elements used in a Command)

## Which versions are affected by CVE-2021-3621?

It affects 8 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libsss_nss_idmap-devel` | AlmaLinux:8 | All versions | 2.4.0-9.el8_4.2 |
| `libipa_hbac` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libipa_hbac-devel` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_autofs` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_certmap` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_certmap-devel` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_idmap` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_idmap-devel` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_nss_idmap` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_nss_idmap-devel` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_simpleifp` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_simpleifp-devel` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_sudo` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `python-libipa_hbac` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `python-libsss_nss_idmap` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `python-sss` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `python-sss-murmur` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `python-sssdconfig` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-ad` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-client` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-common` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-common-pac` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-dbus` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-debuginfo` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-ipa` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-kcm` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-krb5` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-krb5-common` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-ldap` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-libwbclient` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-libwbclient-devel` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-polkit-rules` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-proxy` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-tools` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `sssd-winbind-idmap` | Red Hat:enterprise_linux:7::client | All versions | 0:1.16.5-10.el7_9.10 |
| `libipa_hbac-devel` | Red Hat:enterprise_linux:7::computenode | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_certmap-devel` | Red Hat:enterprise_linux:7::computenode | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_idmap-devel` | Red Hat:enterprise_linux:7::computenode | All versions | 0:1.16.5-10.el7_9.10 |
| `libsss_nss_idmap-devel` | Red Hat:enterprise_linux:7::computenode | All versions | 0:1.16.5-10.el7_9.10 |

Products: Fedoraproject Fedora, Fedoraproject Sssd, Redhat Enterprise Linux, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Tus, Redhat Virtualization, Redhat Virtualization Host.

## How do I fix CVE-2021-3621?

Apply the vendor's patch.

## Is CVE-2021-3621 being exploited?

There is no known exploitation of CVE-2021-3621 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-2021-3621 and fix it if it is affected.

What it is: CVE-2021-3621 is a high-severity command injection vulnerability in Fedoraproject Fedora, published on 23 Dec 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-2021-3621 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-2021-3621/ (Markdown: https://insights.sbomify.com/CVE-2021-3621/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3621
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3621
- OSV: https://osv.dev/vulnerability/CVE-2021-3621

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3621/
Summaries are generated and may contain mistakes; the official description above is the record.