Security Vulnerability CVE-2021-26084 - Complete Analysis and Details
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CVE-2021-26084

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This is a free service offered by Red Hot Cyber to the community. It allows you to view, on a single page, information about a single CVE from the National Vulnerability Database (NVD) and the National Institute of Standards and Technology (NIST) of the United States of America, the Forum of Incident Response and Security Teams (FIRST) regarding the EPSS score and percentile, data from the KEV catalog of the Cybersecurity and Infrastructure Security Agency (CISA), as well as selected resources from Red Hot Cyber and other international sources.

National Vulnerability Database Information

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.

CVSS Base Score: 9.8 (v3.1)

The **CVSS Base Score** is a score from **0 to 10** that represents the intrinsic severity of a vulnerability. A higher score indicates greater severity.

Value
0.02.55.07.510.0
Published on: 08/30/2021 07:15:06
Last modified: 10/24/2025 13:38:44
NIST: CVE source from the National Vulnerability Database (NVD)

CVSS Metrics Details

  • Base Severity: CRITICAL
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Privileges Required: NONE
  • User Interaction: NONE
  • Scope: UNCHANGED
  • Confidentiality Impact: HIGH
  • Integrity Impact: HIGH
  • Availability Impact: HIGH

Common Weakness Enumeration (CWE)

Database CWE: v4.18

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

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.

Fonte: MITRE CWE


FIRST Information

EPSS Score: 0.9444

The **EPSS (Exploit Prediction Scoring System)** is a score from **0 to 1** that indicates the **probability** that a vulnerability will be exploited in the real world in the next 30 days. A higher value indicates a greater likelihood of exploitation.

Value
0.00.250.50.751.0

Percentile: 0.9999

The **Percentile** indicates how much higher this vulnerability's EPSS score is compared to all other vulnerabilities in the EPSS database. For example, a percentile of 0.90 (90%) means that 90% of vulnerabilities have an EPSS score equal to or lower than the current one.

Value
0.00.250.50.751.0

*Data updated as of: 2025-12-12


CISA Information (Known Exploited Vulnerabilities)

The **CISA KEV Catalog** lists vulnerabilities that have been **actively exploited in the real world**. If a CVE is present in this catalog, it indicates that the threat is immediate and mitigation should be a top priority.

CVE **CVE-2021-26084** **IS PRESENT** in the CISA KEV Catalog!

  • Vulnerability Name: Atlassian Confluence Server and Data Center Object-Graph Navigation Language (OGNL) Injection Vulnerability
  • 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.
  • Date Added to KEV: 11/03/2021
  • Vendor/Product: Atlassian / Confluence Server and Data Center
  • Required Action: Apply updates per vendor instructions.
  • Due Date: 11/17/2021

Articles published on Red Hot Cyber


NVD References

Exploit PoC from GitHub