# CVE-2026-21671: Code injection in Software Appliance

> Authenticated Backup Administrators can achieve remote code execution in high availability deployments of Veeam Backup & Replication.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Mar 2026
- **Updated:** 10 May 2026
- **Also known as:** GHSA-9prx-6fqf-vvjh

## What is CVE-2026-21671?

CVE-2026-21671 is a critical code injection vulnerability in Veeam Software Appliance, published on 12 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A vulnerability allowing an authenticated user with the Backup Administrator role to perform remote code execution (RCE) in high availability (HA) deployments of Veeam Backup & Replication.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-21671?

It affects 1 product.


Products: Veeam Veeam Backup \& Replication.

## How do I fix CVE-2026-21671?

No fix has been published for CVE-2026-21671 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21671 being exploited?

There is no known exploitation of CVE-2026-21671 in the wild and no public exploit code.

## Other vulnerabilities in Veeam Software Appliance

- [CVE-2024-40711](https://insights.sbomify.com/CVE-2024-40711/): Veeam Backup and Replication Deserialization (critical 9.8, exploited in the wild)
- [CVE-2022-26501](https://insights.sbomify.com/CVE-2022-26501/): Veeam Backup & Replication Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2022-26500](https://insights.sbomify.com/CVE-2022-26500/): Veeam Backup & Replication Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2023-27532](https://insights.sbomify.com/CVE-2023-27532/): Veeam Backup & Replication Cloud Connect Missing Authentication for Critical Function (high 7.5, exploited in the wild)
- [CVE-2026-21666](https://insights.sbomify.com/CVE-2026-21666/): Missing authorization in Backup and Replication (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21671 and fix it if it is affected.

What it is: CVE-2026-21671 is a critical code injection vulnerability in Veeam Software Appliance, published on 12 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-21671 in the wild and no public exploit code.

Affected product: Veeam Software Appliance. 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-2026-21671/ (Markdown: https://insights.sbomify.com/CVE-2026-21671/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21671
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21671
- OSV: https://osv.dev/vulnerability/CVE-2026-21671

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21671/
Summaries are generated and may contain mistakes; the official description above is the record.