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TI-2021-08036 Aliases CVE-2021-26084GHSA-855c-xp53-5fp2

Expression language injection in Atlassian Confluence Server

Priority CRITICAL 100Exploited in the wildCWE-917Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-917.

Summary

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.

Why it matters now

Exploitation Active In CISA KEV since 2021-11-03CISA due date 2021-11-17Known ransomware use
EPSS 0.99999 99th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed Confluence Server (Atlassian): 6.13.23, 7.4.11, 7.11.6 +1Confluence Data Center (Atlassian): 6.13.23, 7.4.11, 7.11.6 +1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Active
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
AtlassianConfluence Serverbefore 6.13.23; 6.14.0 and later; before 7.4.11; 7.5.0 and later; before 7.11.6; 7.12.0 and later; before 7.12.56.13.23, 7.4.11, 7.11.6, 7.12.5Patch availableCNA
AtlassianConfluence Data Centerbefore 6.13.23; 6.14.0 and later; before 7.4.11; 7.5.0 and later; before 7.11.6; 7.12.0 and later; before 7.12.56.13.23, 7.4.11, 7.11.6, 7.12.5Patch availableCNA
  • Confluence Server VendorAtlassian Affected before 6.13.23; 6.14.0 and later; before 7.4.11; 7.5.0 and later; before 7.11.6; 7.12.0 and later; before 7.12.5 Fixed in 6.13.23, 7.4.11, 7.11.6, 7.12.5 Patch available CNA
  • Confluence Data Center VendorAtlassian Affected before 6.13.23; 6.14.0 and later; before 7.4.11; 7.5.0 and later; before 7.11.6; 7.12.0 and later; before 7.12.5 Fixed in 6.13.23, 7.4.11, 7.11.6, 7.12.5 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*before 6.13.23; 6.14.0 to before 7.4.11; 7.5.0 to before 7.11.6; 7.12.0 to before 7.12.5VulnerableAtlassian
cpe:2.3:a:atlassian:confluence_server:*:*:*:*:*:*:*:*before 6.13.23; 6.14.0 to before 7.4.11; 7.5.0 to before 7.11.6; 7.12.0 to before 7.12.5VulnerableAtlassian
  • cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:* Versions before 6.13.23; 6.14.0 to before 7.4.11; 7.5.0 to before 7.11.6; 7.12.0 to before 7.12.5 Vulnerable ·Atlassian
  • cpe:2.3:a:atlassian:confluence_server:*:*:*:*:*:*:*:* Versions before 6.13.23; 6.14.0 to before 7.4.11; 7.5.0 to before 7.11.6; 7.12.0 to before 7.12.5 Vulnerable ·Atlassian

Remediation

  • Fix · CNA Confluence Server (Atlassian) Fixed in 6.13.23, 7.4.11, 7.11.6, 7.12.5
  • Fix · CNA Confluence Data Center (Atlassian) Fixed in 6.13.23, 7.4.11, 7.11.6, 7.12.5

Timeline

  1. 2021-11-03 Added to CISA KEV
  2. 2026-10-02 Threatist record created from CVE-2021-26084
  3. 2026-10-03 Alias added: GHSA-855c-xp53-5fp2

References

Exploit 1

Patch 1

  • TI-2023-08765 Injection in Atlassian Confluence Data Center KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-08757 Improper input validation in Atlassian Confluence Data Center KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09596 Expression language injection in Atlassian Confluence Data Center KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-67904 Arbitrary file access in Atlassian Data Center products KEVCVSS 4.0CRITICAL 9.3
  • TI-2023-08759 Incorrect authorization in Atlassian Confluence Data Center KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-14399 Code injection in Atlassian Confluence Data Center CVSS 3.1HIGH 8.8
See all 38 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences