Skip to content
Cyber Threat
CTI Academy Sponsor CTI Academy
MEDIUM · CVSS 5.3 CISA Known Exploited Vulnerability

CVE-2021-26086

Atlassian Jira Server and Data Center Path Traversal Vulnerability

Atlassian Jira Server and Data Center

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
5.3
MEDIUM
EPSS
100%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
16 Aug 2021
CWE-22

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 12 November 2024. US federal agencies were required to remediate it by 3 December 2024.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 100%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

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

Frequently asked questions

Is CVE-2021-26086 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2021-26086.

What does CVE-2021-26086 affect?

CVE-2021-26086 affects Atlassian Jira Server and Data Center. 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 is rated MEDIUM with a CVSS base score of 5.3. EPSS puts the probability of exploitation in the next 30 days at 100%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 3 December 2024.

How should organisations respond to CVE-2021-26086?

Apply the vendor patch for Atlassian Jira Server and Data Center as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.