CVE-2021-21311 Adminer Server-Side Request Forgery
Server-side request forgery in Adminer allows attackers to interact with internal services when using the bundled driver version.
- Exploited in the wild
- Since 29 Sep 2025
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-21311?
CVE-2021-21311 is a high-severity server-side request forgery vulnerability in Debian Debian Linux, published on 11 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Adminer is an open-source database management in a single PHP file. In adminer from version 4.0.0 and before 4.7.9 there is a server-side request forgery vulnerability. Users of Adminer versions bundling all drivers (e.g. `adminer.php`) are affected. This is fixed in version 4.7.9.
Weakness: CWE-918
Which versions are affected by CVE-2021-21311?
2 open source packages ship an affected version, including vrana/adminer. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
vrana/adminer Packagist | All versions | 4.7.9 |
vrana/adminer Packagist | All versions | 4.7.9 |
Products include Adminer Adminer, Debian Debian Linux.
How do I fix CVE-2021-21311?
Upgrade vrana/adminer to 4.7.9 or later. US federal agencies must fix it by 20 Oct 2025.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2021-21311 being exploited?
Yes. Attackers have exploited CVE-2021-21311 in the wild since at least 29 Sep 2025.
Public exploit code: 1 Nuclei template and 3 proofs of concept on GitHub.
Other vulnerabilities in Debian Debian Linux
- CVE-2018-7667 vrana/adminer vulnerable to SSRF by connecting to privileged ports
- CVE-2025-43960 Adminer PHP Object Injection issue leads to Denial of Service
- CVE-2026-25892 Adminer has an Unauthenticated Persistent DoS via Array Injection in ?script=version Endpoint
- CVE-2021-43008 Files or Directories Accessible to External Parties in Adminer
- CVE-2021-29625 XSS in doc_link
Sources
Also known as DEBIAN-CVE-2021-21311, DLA-2580-1, GHSA-x5r2-hj5c-8jx6, UBUNTU-CVE-2021-21311.