VulnTideExploited vulnerabilities, by vendor. Data as of .
Known exploitedIn CISA's KEV catalog since Ransomware use: known
Atlassian Confluence Server and Data Center

CVE-2021-26084: Atlassian Confluence Server and Data Center Object-Graph Navigation Language (OGNL) Injection Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 65 days after the CVE record was published.

How likely is exploitation in the next 30 days?
100%

EPSS score, percentile 100 of all scored records

How severe?
9.8 Critical

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA deadline . Apply updates per vendor instructions.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • before 6.13.23
  • 6.14.0
  • before 7.4.11
  • 7.5.0
  • before 7.11.6
  • 7.12.0

and 8 more in the table below

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

What to do

Required action, set by CISA

Apply updates per vendor instructions.

CISA due date for this action: .

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Atlassian Confluence Server
StatusVersions
Affectedbefore 6.13.23
Affected6.14.0
Affectedbefore 7.4.11
Affected7.5.0
Affectedbefore 7.11.6
Affected7.12.0
Affectedbefore 7.12.5
Atlassian Confluence Data Center
StatusVersions
Affectedbefore 6.13.23
Affected6.14.0
Affectedbefore 7.4.11
Affected7.5.0
Affectedbefore 7.11.6
Affected7.12.0
Affectedbefore 7.12.5

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

About this vulnerability

Atlassian Confluence Server and Data Server contain an Object-Graph Navigation Language (OGNL) injection vulnerability that may allow an unauthenticated attacker to execute code.

Summary: CISA's KEV catalog, as of .

  • CISA added CVE-2021-26084 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
  • CISA marks it as known to be used in ransomware campaigns.
  • The due date CISA sets for the required action is 17 Nov 2021.
  • The CVE record was published on 30 Aug 2021, 65 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), taken from CISA's enrichment of the record.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 100% (percentile 100), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

Weakness

  • CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
CVE record published
Added to CISA KEV
CISA due date for the required action
CVE record last updated

References

More exploited Atlassian vulnerabilities

  • CVE-2026-21589: Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability (added )
  • CVE-2021-26086: Atlassian Jira Server and Data Center Path Traversal Vulnerability (added )
  • CVE-2023-22527: Atlassian Confluence Data Center and Server Template Injection Vulnerability (added )
  • CVE-2023-22518: Atlassian Confluence Data Center and Server Improper Authorization Vulnerability (added )
  • CVE-2023-22515: Atlassian Confluence Data Center and Server Broken Access Control Vulnerability (added )
  • CVE-2022-36804: Atlassian Bitbucket Server and Data Center Command Injection Vulnerability (added )