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CVE-2021-26084

9.8, critical Known exploited Used in ransomware

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

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
9.8, critical critical CVSS v3.1
EPSS, next 30 days
100% higher than 99.9% of scored CVEs
Exploitation
Confirmed in the wild
Published
30 Aug 20215 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 3 Nov 2021 and links it to ransomware activity. US federal agencies had to remediate by 17 Nov 2021, a deadline that has passed.

Required action. Apply updates per vendor instructions.

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.

Details

Vendor
Atlassian
Product
Confluence Server
Weakness
CWE-917 (opens in a new tab)
Status
Analyzed
Updated
17 Jun 2026
Assigner
security@atlassian.com

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

References 3

Exploit code 1

Patches and fixes 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Atlassian CVEs

Every Atlassian CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-21589 Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability KEV EPSS 13% 7.5, high
  • CVE-2023-22527 Atlassian Confluence Data Center and Server Template Injection Vulnerability KEV EPSS 100% 9.8, critical
  • CVE-2023-22518 Atlassian Confluence Data Center and Server Improper Authorization Vulnerability KEV EPSS 100% 9.8, critical
  • CVE-2023-22515 Atlassian Confluence Data Center and Server Broken Access Control Vulnerability KEV EPSS 99% 9.8, critical
  • CVE-2022-36804 Atlassian Bitbucket Server and Data Center Command Injection Vulnerability KEV EPSS 99% 8.8, high
  • CVE-2022-26138 Atlassian Questions For Confluence App Hard-coded Credentials Vulnerability KEV EPSS 98% 9.8, critical
  • CVE-2022-26134 Atlassian Confluence Server and Data Center Remote Code Execution Vulnerability KEV EPSS 100% 9.8, critical
  • CVE-2021-26086 Atlassian Jira Server and Data Center Path Traversal Vulnerability KEV EPSS 100% 5.3, medium

Beyond this page

Is CVE-2021-26084 in your network?

This page tells you how dangerous CVE-2021-26084 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2021-26084 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.