CVE-2021-21311
SSRF in Adminer 4.0.0 – 4.7.9
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:NSummary
CVE-2021-21311 is a high-severity SSRF (CWE-918) vulnerability in Adminer Adminer. Its CVSS base score is 7.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Adminer is an open-source database management tool distributed as a single PHP file. It is affected by a server-side request forgery vulnerability in versions 4.0.0 through 4.7.8 that impacts users of builds bundling all drivers, such as adminer.php. The flaw is identified as CWE-918 and carries a CVSS 3.1 score of 7.2.
An unauthenticated remote attacker can send crafted requests to the Adminer instance to induce the server into making arbitrary outbound connections, resulting in limited impacts to confidentiality and integrity in the server's security context.
The issue is resolved in version 4.7.9. The project has published a security advisory and corresponding code commit, while Debian has issued an LTS announcement and the package metadata is tracked on Packagist to support patching.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-0576
Vulnerability Data
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…
more
in version 4.7.9.
- CWE(s)
- KEV Date Added
- 29 September 2025
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.
Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.
Validates server-side URLs and resource references to block SSRF attempts.
Detects server-side request forgery through monitoring of unexpected outbound connections.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices directly include input validation and destination allow-listing that prevent SSRF.
Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.
Vulnerability identification processes can discover and record SSRF flaws in web applications.
Network segmentation and egress controls can limit the damage from successful SSRF requests.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.