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PatchSiren cyber security CVE debrief

CVE-2021-26086 Atlassian CVE debrief

CVE-2021-26086 is a path traversal vulnerability in Atlassian Jira Server and Data Center that CISA lists in its Known Exploited Vulnerabilities catalog. For defenders, the key point is not just the vulnerability type, but that it is treated as actively exploited in the wild and has a CISA remediation deadline. Follow vendor instructions for mitigations; if mitigations are unavailable, CISA directs organizations to discontinue use of the product.

Vendor
Atlassian
Product
Jira Server and Data Center
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2024-11-12
Original CVE updated
2024-11-12
Advisory published
2024-11-12
Advisory updated
2024-11-12

Who should care

Administrators and security teams responsible for Atlassian Jira Server and Data Center deployments, especially organizations that expose Jira to internal or external users and those that track CISA KEV items for patching and risk acceptance decisions.

Technical summary

The supplied source corpus identifies CVE-2021-26086 as a path traversal issue affecting Atlassian Jira Server and Data Center. CISA’s KEV entry indicates the vulnerability is known to be exploited and instructs defenders to apply mitigations per vendor guidance or stop using the product if mitigations are unavailable. No CVSS score or exploit details were provided in the source set, so this debrief limits itself to the confirmed vulnerability class and remediation guidance.

Defensive priority

High. This is a CISA Known Exploited Vulnerability with a stated remediation due date, so it should be prioritized ahead of non-KEV issues in the same environment.

Recommended defensive actions

  • Verify whether any Jira Server or Data Center instances are present in your environment.
  • Check the Atlassian vendor guidance referenced by CISA for mitigations and apply them promptly.
  • If mitigations are unavailable or cannot be deployed in time, follow CISA guidance to discontinue use of the product.
  • Track the CISA KEV due date of 2024-12-03 as an escalation deadline.
  • Validate that compensating controls, monitoring, and access restrictions are in place until remediation is complete.

Evidence notes

The debrief is based on the supplied CISA KEV record for CVE-2021-26086, which names Atlassian Jira Server and Data Center and classifies the issue as a path traversal vulnerability. The CISA metadata includes the remediation instruction to apply vendor mitigations or discontinue use if mitigations are unavailable. Official reference links supplied in the corpus include the CVE record, NVD detail page, and CISA KEV catalog. No CVSS score, affected-version range, or exploit narrative was provided in the source corpus, so those details are intentionally omitted.

Official resources

Supplied timeline data shows CVE published/modified on 2024-11-12, and CISA added the item to KEV on 2024-11-12 with a due date of 2024-12-03. This debrief does not infer any earlier or later publication dates beyond the provided corpus.