UpHeron
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Servers and applications

CVE-2021-26084

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.

Actively exploited: CISA added it to its Known Exploited Vulnerabilities catalog on 3 Nov 2021.

Severity
Critical 9.8
Published
30 Aug 2021
Last changed
17 Jun 2026
Added to UpHeron
21 Oct 2026
Fixed in
6.13.23, 7.4.11, 7.11.6, 7.12.5
Sources
NVD

Affected software

SoftwareAffected versions
ConfluenceServers and applications · cpe:a:atlassian:confluence_data_center
  • Every version before 6.13.23
  • From 6.14.0 before 7.4.11
  • From 7.5.0 before 7.11.6
  • From 7.12.0 before 7.12.5
ConfluenceServers and applications · cpe:a:atlassian:confluence_server
  • Every version before 6.13.23
  • From 6.14.0 before 7.4.11
  • From 7.5.0 before 7.11.6
  • From 7.12.0 before 7.12.5

Known exploited

CISA name
Atlassian Confluence Server and Data Center Object-Graph Navigation Language (OGNL) Injection Vulnerability
Required action
Apply updates per vendor instructions.
Due for US agencies
17 Nov 2021
Used in ransomware
Yes, known

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2021-26084
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2021-26084