CVE-2021-21311 — Adminer Server-Side Request Forgery Vulnerability

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.

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
vrana	adminer	>= 4.0.0, < 4.7.9

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2025-09-29. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2021-02-11T20:55:15.000Z
• Last modified: 2025-10-21T23:35:27.923Z
• Added to CISA KEV: 2025-09-29
• BOD 22-01 due: 2025-10-20

09References

• github.com — https://github.com/vrana/adminer/security/advisories/GHSA-x5r2-hj5c-8jx6
• github.com — https://github.com/vrana/adminer/files/5957311/Adminer.SSRF.pdf
• packagist.org — https://packagist.org/packages/vrana/adminer
• github.com — https://github.com/vrana/adminer/commit/ccd2374b0b12bd547417bf0dacdf153826c83351
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2021/03/msg00002.html