Is CVE-2021-26084 in the CISA KEV catalog?

Yes. CVE-2021-26084 is on the CISA Known Exploited Vulnerabilities list, added 2021-11-03, and has known ransomware campaign use.

What is the CVSS severity of CVE-2021-26084?

CVE-2021-26084 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2021-26084?

CVE-2021-26084 has an EPSS score of 100.00% (100th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-26084?

Upgrade confluence data center to 7.12.5 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2021-26084

CRITICALCISA KEVEPSS 100th pctl

9.8

CVSS v3

NVD

Description

In affected versions of Confluence Server and Data Center, an OGNL injection vulnerability exists that would allow an unauthenticated attacker to execute arbitrary code on a Confluence Server or Data Center instance. The affected versions are before version 6.13.23, from version 6.14.0 before 7.4.11, from version 7.5.0 before 7.11.6, and from version 7.12.0 before 7.12.5.

CWE-917

How to fix

Remediation Available

confluence data centerNVD

Affected:>= 7.12.0, < 7.12.5Fixed in:7.12.5CVE-2021-26084derived from NVD

confluence serverNVD

Affected:>= 7.12.0, < 7.12.5Fixed in:7.12.5CVE-2021-26084derived from NVD

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

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

100.00%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)

Atlassian Confluence Server and Data Center Object-Graph Navigation Language (OGNL) Injection Vulnerability

Atlassian Confluence Server and Data Server contain an Object-Graph Navigation Language (OGNL) injection vulnerability that may allow an unauthenticated attacker to execute code.

Apply updates per vendor instructions.

Remediation due: 2021-11-17

Associated with ransomware campaigns

References

Patch1

jira.atlassian.com

Exploit1

packetstormsecurity.com

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-917 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-26134	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2021-45046	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2022-22963	Critical	9.8	100%	KEV	-
CVE-2020-10199	High	8.8	99%	KEV	Fix
CVE-2022-22947	Critical	10.0	98%	KEV	Fix

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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.