CVE-2021-26086 — Jira Data Center
MEDIUMCVE-2021-26086 is a medium-severity (CVSS 5.3) Path Traversal vulnerability in atlassian jira data center. It is in CISA's Known Exploited Vulnerabilities catalog (added 2024-11-12) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
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…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2024-11-12. Federal agencies were required to remediate by 2024-12-03.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2021-26086.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-26086 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
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.
Affected Products
jira data centeratlassianjira serveratlassianResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Atlassian Jira Server Data Center 8.16.0 - Arbitrary File Read
by Mayank Deshmukh · Oct 6, 2021
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every atlassian jira data center deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2021-26086 yet — track the atlassian jira data center advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
How to detect CVE-2021-26086
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2021-26086 -u https://target- Template
- Atlassian Jira Limited - Local File Inclusion
- Severity
- medium
- Impact
- This vulnerability can result in unauthorized access to sensitive files and data, as well as potential remote code execution, leading to a complete compromise of the affected system.
- Remediation
- Apply the latest security patches and updates provided by Atlassian to mitigate this vulnerability.
Template by ProjectDiscovery nuclei-templates (cocxanh), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2021-26086 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.