--- title: "CVE-2021-26084: Atlassian Confluence Server vulnerability | CubePath" description: "In affected versions of Confluence Server and Data Center, an OGNL injection vulnerability exists that would allow an unauthenticated attacker to execute…" language: en source: https://cubepath.com/security/cve/CVE-2021-26084 --- # CVE-2021-26084: Atlassian Confluence Server vulnerability | CubePath ## 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. Official description from the CVE record, published by atlassian. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2021-26084) ## Key data ### CVSS 3.1 Critical 9.8 Score published by CISA-ADP in the CVE record. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | Metric | Value | What it means | | ---------------------- | --------- | ----------------------------------------------------------------------------------- | | Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. | | Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. | | Privileges required | None | No account or privileges are needed. | | User interaction | None | No action from any user is needed. | | Scope | Unchanged | The impact stays within the vulnerable component. | | Confidentiality impact | High | Serious or total effect on the secrecy of data. | | Integrity impact | High | Serious or total effect on the trustworthiness of data. | | Availability impact | High | Serious or total effect on availability. | CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) . ### EPSS Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days. Score 0.99999 (99.99% probability) Percentile 99.99% Scores of Nov 10, 2026 Model v2026.06.15 ### CISA Known Exploited Vulnerabilities This CVE is listed in the CISA KEV catalog. Name in the catalog Atlassian Confluence Server and Data Center Object-Graph Navigation Language (OGNL) Injection Vulnerability Added to the catalog Nov 3, 2021 Federal due date Nov 17, 2021 Ransomware campaigns Known use ### CISA assessment as of Dec 16, 2025 Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA. Exploitation Recorded by CISA as active Automatable yes Technical impact total ### Weakness (CWE) CWE catalog version 5.0. CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license. - [CWE-917](https://cwe.mitre.org/data/definitions/917.html) Improper Neutralization of Special Elements used in an Expression Language Statement ## Affected products Products listed in the CVE record, as the CNA published them. - Atlassian Confluence Server - affected: unspecified up to before 6.13.23 - affected: 6.14.0 up to before unspecified - affected: unspecified up to before 7.4.11 - affected: 7.5.0 up to before unspecified - affected: unspecified up to before 7.11.6 - affected: 7.12.0 up to before unspecified - affected: unspecified up to before 7.12.5 - Atlassian Confluence Data Center - affected: unspecified up to before 6.13.23 - affected: 6.14.0 up to before unspecified - affected: unspecified up to before 7.4.11 - affected: 7.5.0 up to before unspecified - affected: unspecified up to before 7.11.6 - affected: 7.12.0 up to before unspecified - affected: unspecified up to before 7.12.5 ## References Links listed in the CVE record. They lead to other sites, which CubePath does not control. - [jira.atlassian.com/browse/CONFSERVER-67940](https://jira.atlassian.com/browse/CONFSERVER-67940) - [packetstormsecurity.com/files/167449/Atlassian-Confluence-N…](http://packetstormsecurity.com/files/167449/Atlassian-Confluence-Namespace-OGNL-Injection.html) ## Timeline 1. ID reserved Jan 25, 2021 2. Record published Aug 30, 2021 3. Added to CISA KEV Nov 3, 2021 4. Record last updated Dec 16, 2025 ## Look up another CVE ## About CubePath CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection. [Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection) Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 20:04 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)