CVE-2021-26086 Atlassian Jira Server and Data Center: file path flaw
In plain words: The program can be tricked into reading or writing files outside the folder it should stay in. Leaks files such as passwords and settings, or overwrites important ones.
Confirmed exploited by CISA on · US federal patch deadline Dec 3, 2024
What to do
- Install Atlassian's security update for Jira Server and Data Center. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- Atlassian Jira Server and Data Center Path Traversal Vulnerability
- Product
- Atlassian Jira Server and Data Center
- CISA description
- Atlassian Jira Server and Data Center contain a path traversal vulnerability that allows a remote attacker to read particular files in the /WEB-INF/web.xml endpoint.
- Type of flaw
- File path flaw (CWE-22)
- Confirmed exploited
- Nov 12, 2024
- US federal patch deadline
- Dec 3, 2024
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Answering about CVE-2021-26086 ·
Questions about CVE-2021-26086
Is CVE-2021-26086 being exploited?
Yes. CISA added CVE-2021-26086 to its Known Exploited Vulnerabilities catalog on Nov 12, 2024, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2021-26086?
Install Atlassian's security update for Jira Server and Data Center. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2021-26086?
Only if you use Atlassian Jira Server and Data Center. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.