CVE-2021-26085 Atlassian Confluence Server: login or permission bypass
In plain words: A door that should be locked is not: part of the system can be reached without a valid login or permission. The attacker gets in as a user or administrator without knowing a password.
Confirmed exploited by CISA on · US federal patch deadline Apr 18, 2022
What to do
- Install Atlassian's security update for Confluence Server. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
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: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
- Product
- Atlassian Confluence Server
- CISA description
- Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a pre-authorization arbitrary file read vulnerability in the /s/ endpoint.
- Type of flaw
- Login or permission bypass (CWE-425)
- Confirmed exploited
- Mar 28, 2022 — known to be used in ransomware attacks
- US federal patch deadline
- Apr 18, 2022
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Answering about CVE-2021-26085 ·
Questions about CVE-2021-26085
Is CVE-2021-26085 being exploited?
Yes. CISA added CVE-2021-26085 to its Known Exploited Vulnerabilities catalog on Mar 28, 2022, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2021-26085?
Install Atlassian's security update for Confluence Server. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2021-26085?
Only if you use Atlassian Confluence Server. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.