Historical catalog analysis: CISA added this entry on November 12, 2024. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.
What the vulnerability is
CVE-2021-26086 is a path traversal vulnerability (CWE-22) affecting Atlassian Jira Server and Data Center. This flaw allows a remote attacker to read specific files by targeting the /WEB-INF/web.xml endpoint.
Exposure and applicability
This vulnerability applies to organizations running Atlassian Jira in either the Server or Data Center deployment models. The exposure path is network-based, as the source indicates that a remote attacker can trigger the file read. Infrastructure owners should identify all active Jira instances within their environment to determine if they are susceptible to this specific endpoint traversal.
Remediation priorities
Based on our analysis, remediation should be prioritized for Jira instances that are exposed to untrusted networks or those handling highly sensitive configuration data.
- Apply Vendor Mitigations: The primary corrective action is the application of mitigations provided by Atlassian. This is the most direct method to reduce exposure.
- Product Decommissioning: In scenarios where vendor mitigations cannot be applied or are unavailable for a specific legacy version, our analysis suggests discontinuing use of the product to eliminate the risk entirely.
How to validate remediation
Verification must go beyond a simple version check, as a version number does not inherently prove that the necessary mitigation has been successfully deployed and is active.
Defenders should verify the result by confirming that the /WEB-INF/web.xml endpoint no longer permits unauthorized remote file reads. Validation evidence should consist of logs or test results showing that requests to this path are properly blocked or handled according to the vendor’s security specifications. A successful validation confirms that the exposure has been reduced, rather than just noting that a patch was installed.
Limits and open questions
While the vulnerability is documented, there are remaining uncertainties. The source lists known ransomware campaign use as “Unknown,” meaning it is unclear if this flaw has been integrated into broader automated attack frameworks. Additionally, while the vulnerability allows reading “particular files,” the full scope of accessible system files beyond the specified endpoint remains a point for further investigation by the asset owner.
Source and editorial note
CVE-2021-26086: Atlassian Jira Server and Data Center Path Traversal Vulnerability · Source date: November 12, 2024 · Retrieved August 31, 2026.
Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.
Archive date: November 15, 2024. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: November 04, 2026 at 00:44 UTC.
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