How severe is CVE-2021-26086?

CVE-2021-26086 has a CVSS 3.1 base score of 5.3 (MEDIUM). EPSS estimates a 100.0% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2021-26086: Atlassian Jira Server and Data Center Path Traversal

CISA Known Exploited Vulnerabilities

Atlassian Jira Server and Data Center Path Traversal Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2024-11-12

Remediation due

2024-12-03

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

CISA notes
https://jira.atlassian.com/browse/JRASERVER-72695 ; https://nvd.nist.gov/vuln/detail/CVE-2021-26086

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.

Severity

CVSS 3.1 · CISA5.3 MEDIUM

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

SSVC · CISA-ADP

Exploitationactive

Automatableyes

Technical impactpartial

Exploitation Context

as of October 14, 2026

All KEV statistics→

CISA added CVE-2021-26086 to the KEV catalog 1,184 days after its CVE record was published. The median for entries added in 2024 is 21.5 days.
It is one of 13 Atlassian entries in the CISA KEV catalog, and one of 2 added in 2024.
Its current EPSS score (100.0%) is higher than that of 97% of CISA KEV entries.

Affected Products

Vendor	Product	Affected versions
Atlassian	Atlassian Jira Server	unspecified to <8.5.14 8.6.0 to <unspecified unspecified to <8.13.6 8.14.0 to <unspecified unspecified to <8.16.1
Atlassian	Atlassian Jira Data Center	unspecified to <8.5.14 8.6.0 to <unspecified unspecified to <8.13.6 8.14.0 to <unspecified unspecified to <8.16.1

References

2 Links

Other references

Record Details

Published

2021-08-16

Last updated

2025-10-21

Assigner (CNA)

atlassian

Credited to

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CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.