Is CVE-2021-21311 in the CISA KEV catalog?

Yes. CVE-2021-21311 is on the CISA Known Exploited Vulnerabilities list, added 2025-09-29.

What is the CVSS severity of CVE-2021-21311?

CVE-2021-21311 has a CVSS v3 base score of 7.2 (HIGH).

What is the EPSS score for CVE-2021-21311?

CVE-2021-21311 has an EPSS score of 90.07% (100th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21311?

Upgrade adminer on debian 11 to 4.7.9-1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2021-21311

HIGHCISA KEVEPSS 100th pctl

7.2

CVSS v3

NVD

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.

CWE-918Server-Side Request Forgery (SSRF)

How to fix

Remediation Available

adminerDebian

Fixed in:4.7.9-1CVE-2021-21311

adminerUbuntu

Fixed in:4.2.1-1ubuntu1+esm1USN-5271-1

Fixed in:4.6.2-1ubuntu0.1~esm1USN-5271-1

Fixed in:4.7.6-1ubuntu0.1~esm1USN-5271-1

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

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Exploit Intelligence

90.07%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

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

Patch2

Exploit1

github.com

Third-Party Advisory2

Government Resource1

cisa.gov

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	Fix
CVE-2021-34473	Critical	9.1	100%	KEV + Ransom	Fix
CVE-2021-26855	Critical	9.1	100%	KEV + Ransom	Fix
CVE-2021-21985	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2022-41040	High	8.8	100%	KEV + Ransom	Fix

Embed a live status badge for CVE-2021-21311

Markdown

[![CVE-2021-21311](https://tridentstack.com/cve/badge/CVE-2021-21311.svg)](https://tridentstack.com/cve/CVE-2021-21311)

HTML

<a href="https://tridentstack.com/cve/CVE-2021-21311"><img src="https://tridentstack.com/cve/badge/CVE-2021-21311.svg" alt="CVE-2021-21311"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

See how it works Start freeThis CVE lookup is free and always will be.

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.