November 3, 2021 · Applied Cybernetics Group
CVE-2021-26084 — Atlassian Confluence Server and Data Center
known ransomware use
Atlassian Confluence Server and Data Center Object-Graph Navigation Language (OGNL) Injection Vulnerability
- Added to KEV
2021-11-03- Federal due date
2021-11-17- Vendor
- Atlassian
- Product
- Confluence Server and Data Center
- EPSS
- 100.0th percentile (score 1.000, as of
2026-07-13) - NVD CVSS v3.1
- —
- Ransomware use
- Known
- ATT&CK
- T1059 , T1496 · signal rollup
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2021-26084
CISA short description
Atlassian Confluence Server and Data Server contain an Object-Graph Navigation Language (OGNL) injection vulnerability that may allow an unauthenticated attacker to execute code.
Required action
Apply updates per vendor instructions.