How severe is CVE-2021-21311?

CVE-2021-21311 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-21311 being actively exploited?

Yes. CVE-2021-21311 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-09-29, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-21311?

CVE-2021-21311 primarily affects Adminer. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21311?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-21311 have an EU (EUVD) identifier?

Yes. CVE-2021-21311 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-0576. It is also flagged as exploited in the EUVD (since 2025-09-29).

When was CVE-2021-21311 published?

CVE-2021-21311 was published on 2021-02-11 and last updated on 2026-06-17.

CVE-2021-21311

CVE-2021-21311 is a high-severity vulnerability in Adminer with a CVSS 3.x base score of 7.2. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2025-09-29). The underlying weakness is classified as CWE-918.

Key facts

Severity: High (CVSS 3.x base score 7.2)
CVSS v2: 6.4
EPSS exploit prediction: 90% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2025-09-29)
EU (EUVD) id: EUVD-2021-0576
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2025-09-29)
Weakness: CWE-918
Affected product: Adminer
Published: 2021-02-11
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-21311?: 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 severe is CVE-2021-21311?: CVE-2021-21311 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-21311 being actively exploited?: Yes. CVE-2021-21311 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-09-29, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-21311?: CVE-2021-21311 primarily affects Adminer. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21311?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-21311 have an EU (EUVD) identifier?: Yes. CVE-2021-21311 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-0576. It is also flagged as exploited in the EUVD (since 2025-09-29).
When was CVE-2021-21311 published?: CVE-2021-21311 was published on 2021-02-11 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:adminer:adminer:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

More vulnerabilities in Adminer

CVE-2018-7667 — Critical (CVSS 9.8): Adminer through 4.3.1 has SSRF via the server parameter.
CVE-2025-43960 — High (CVSS 8.6): Adminer 4.8.1, when using Monolog for logging, allows a Denial of Service (memory consumption) via a crafted serialized…
CVE-2026-25892 — High (CVSS 7.5): Adminer is open-source database management software. Adminer v5.4.1 and earlier has a version check mechanism where…
CVE-2021-43008 — High (CVSS 7.5): Improper Access Control in Adminer versions 1.12.0 to 4.6.2 (fixed in version 4.6.3) allows an attacker to achieve…
CVE-2021-29625 — High (CVSS 7.5): Adminer is open-source database management software. A cross-site scripting vulnerability in Adminer versions 4.6.1 to…
CVE-2020-35572 — Medium (CVSS 6.1): Adminer through 4.7.8 allows XSS via the history parameter to the default URI.

All CVEs affecting Adminer →

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