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

CVE-2021-26084 is rated critical with a CVSS v3.1 base score of 9.8 and affects Atlassian Confluence Server and Data Center, along with 1 other product in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2021-11-03, which means exploitation in the wild has been observed.

Vulnerability 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.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.

Affected products

  • Atlassian Confluence Server: 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
  • Atlassian Confluence Data Center: 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

References