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CVE-2021-26086 CISA KEV — actively exploited

Atlassian Jira Server and Data Center Path Traversal Vulnerability

Atlassian — Jira Server

Affected versions of Atlassian Jira Server and Data Center allow remote attackers to read particular files via a path traversal vulnerability in the /WEB-INF/web.xml endpoint. The affected versions are before version 8.5.14, from version 8.6.0 before 8.13.6, and from version 8.14.0 before 8.16.1.

CVSS scoreMedium

5.3

EPSS — exploitation probabilityCritical

100.0%

Vector breakdown

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Published
Aug 16, 2021
Modified
Oct 21, 2025
Added to KEV
Nov 12, 2024
Federal patch due
Dec 3, 2024

CISA required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Weakness classification

CWE-22Improper Limitation of a Pathname to a Restricted Directory

Proof-of-concept & exploitation references

Weaponization

Nuclei template

Available

Metasploit module

Not found

Public repositories whose name or description references CVE-2021-26086, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.

No public GitHub repositories referencing CVE-2021-26086 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.

References

  • jira.atlassian.com
  • packetstormsecurity.com

Frequently asked questions

What is CVE-2021-26086?

Affected versions of Atlassian Jira Server and Data Center allow remote attackers to read particular files via a path traversal vulnerability in the /WEB-INF/web.xml endpoint. The affected versions are before version 8.5.14, from version 8.6.0 before 8.13.6, and from version 8.14.0 before 8.16.1.

How severe is CVE-2021-26086?

CVE-2021-26086 has a CVSS base score of 5.3 out of 10 (CVSS 3.1).

Is CVE-2021-26086 actively exploited in the wild?

Yes. CVE-2021-26086 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Nov 12, 2024, meaning CISA has confirmed evidence of active exploitation.

What is the EPSS score for CVE-2021-26086?

100.0% - meaning FIRST.org's EPSS model estimates a 100.0% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).

Is there exploit tooling available for CVE-2021-26086?

Yes - a public Nuclei template referencing CVE-2021-26086 exist in public repositories we checked.

What type of vulnerability is CVE-2021-26086?

CVE-2021-26086 is classified under CWE-22 (CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')).

Cross-checked against

  • NVD (NIST)
  • MITRE CVE Record
  • CISA KEV
  • FIRST.org EPSS
  • GitHub Advisory Database
  • GitHub public repository search

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