CVE-2021-21311
HIGHCISA KEVEPSS 100th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Exploit Intelligence
Very high risk: more likely to be exploited than 100% of all known CVEs.
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.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Remediation due: 2025-10-20
References
Related Vulnerabilities
Other CWE-918 (Server-Side Request Forgery (SSRF)) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-21893 | High | 8.2 | 100% | KEV + Ransom | - |
| CVE-2021-40438 | Critical | 9.0 | 100% | KEV + Ransom | Fix |
| CVE-2021-34473 | Critical | 9.1 | 100% | KEV + Ransom | Fix |
| CVE-2021-21985 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2021-26855 | Critical | 9.1 | 100% | KEV + Ransom | Fix |
| CVE-2022-41040 | High | 8.8 | 100% | KEV + Ransom | Fix |
Common questions
How do I fix CVE-2021-21311?
Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2021-21311 being actively exploited?
Yes. CVE-2021-21311 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2025-10-20. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2021-21311?
CVE-2021-21311 has a CVSS v3 base score of 7.2, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-21311 affect?
Published advisories record a fix for adminer (Debian), adminer (Ubuntu). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-24.