IRONSMITHINTEL
HIGHCVSS7.2
|
Actively Exploited
|CISA KEV|CVE-2021-21311|Auth: none — unauthenticated|Reboot: required|Manual only

Adminer Server-Side Request Forgery Vulnerability

Adminer contains a server-side request forgery vulnerability that, when exploited, allows a remote attacker to obtain potentially sensitive information.

Published Feb 11, 2021 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve partial data exposure, partial data tampering. Federal agencies are required to remediate by 2025-10-20 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Server-Side Request Forgery (SSRF) (CWE-918) vulnerability in Adminer Adminer. 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. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

📧

Phishing link

🖼

Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running adminer: 4.0.0 ≤ v < 4.7.9; debian linux: 9.0
Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://github.com/vrana/adminer/files/5957311/Adminer.SSRF.pdf

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

References

    1
    Vendor advisory: https://github.com/vrana/adminer/security/advisories/GHSA-x5r2-hj5c-8jx6
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2021-21311
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21311
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