CVE-2021-26084

CRITICAL9.8

CISA KEV

Published 2021-08-30 · Updated 2026-06-17 · Source security@atlassian.com

Summary

CVE-2021-26084 is a critical-severity (CVSS 9.8) vulnerability in Atlassian Confluence Server and Data Center. CISA added it to the Known Exploited Vulnerabilities catalog on November 3, 2021, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by November 17, 2021. CISA also lists it as known to be used in ransomware campaigns, so it should be prioritised accordingly. Atlassian has 14 vulnerabilities in the KEV catalog, 8 of them linked to ransomware.

All 14 known-exploited Atlassian vulnerabilities →

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.

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

CWE-917CWE-917

CISA Known-Exploited Vulnerability

Product: Atlassian — Confluence Server and Data Center

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

Date added: 2021-11-03 · Due: 2021-11-17

USED IN RANSOMWARE

Required action: Apply updates per vendor instructions.

References

View on NVD

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added 2023-10-05
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added 2022-09-30

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