Background exploitation KEV catalog Ransomware No authentication

CVE-2021-26085

Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability

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. The affected versions are before version 7.4.10, and from…

CheckOps priority index

8.1/10 Patch within 24 h

Severity5.3

Probability10.0

Exploitation5/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 99.9% higher than 99.97% of CVEs

CVSS 3.1 5.3 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:

Exploited for 1,681 days 28 Mar 2022

CISA due date 18 Apr 2022 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 5 / 5

KEV catalog (CISA)28 Mar 2022
Exploited in EUVD (ENISA)28 Mar 2022
Used by ransomwareyes
EPSS above 10 %99.9%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

Affected products

Confluence Data CenterConfluence Server

Affected versions

unspecified <7.4.10
7.5.0 <unspecified
unspecified <7.12.3

Weaknesses (CWE)

CWE-425

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

03 Aug 2021
Published
28 Mar 2022
Exploitation reported (ENISA)
28 Mar 2022
Added to the KEV catalog
18 Apr 2022
CISA remediation due date
26 Sept 2026
EPSS peak: 99.9%

References

Other exploited vulnerabilities from the same vendor

CVE-2026-21589Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability
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CVE-2021-26086Atlassian Jira Server and Data Center Path Traversal Vulnerability
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CVE-2023-22527Atlassian Confluence Data Center and Server Template Injection Vulnerability
10.0 · Background exploitation
CVE-2023-22518Atlassian Confluence Data Center and Server Improper Authorization Vulnerability
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CVE-2023-22515Atlassian Confluence Data Center and Server Broken Access Control Vulnerability
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CVE-2022-36804Atlassian Bitbucket Server and Data Center Command Injection Vulnerability
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