CVE-2021-26084

Name: CVE-2021-26084
Creator: NVD / NIST
Published: 2021-08-30T07:15:06.587+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10Actively ExploitedEPSS 100.00%

Last modified Jun 17, 2026

CVE-2021-26084 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. CISA has confirmed active exploitation in the wild. EPSS estimates a 100.00% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

100.00%

100.0th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Nov 17, 2021.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Atlassian	Confluence Data Center	< 6.13.23
Atlassian	Confluence Data Center	>= 6.14.0, < 7.4.11
Atlassian	Confluence Data Center	>= 7.5.0, < 7.11.6
Atlassian	Confluence Data Center	>= 7.12.0, < 7.12.5
Atlassian	Confluence Server	< 6.13.23
Atlassian	Confluence Server	>= 6.14.0, < 7.4.11
Atlassian	Confluence Server	>= 7.5.0, < 7.11.6
Atlassian	Confluence Server	>= 7.12.0, < 7.12.5

References

http://packetstormsecurity.com/files/167449/Atlassian-Confluence-Namespace-OGNL-Injection.htmlExploit, Third Party Advisory, VDB Entry
https://jira.atlassian.com/browse/CONFSERVER-67940Issue Tracking, Patch, Vendor Advisory
http://packetstormsecurity.com/files/167449/Atlassian-Confluence-Namespace-OGNL-Injection.htmlExploit, Third Party Advisory, VDB Entry
https://jira.atlassian.com/browse/CONFSERVER-67940Issue Tracking, Patch, Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26084US Government Resource

Timeline

Published: Aug 30, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-26084?

How severe is CVE-2021-26084?

CVE-2021-26084 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 100.00% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-26084?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-26084?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST