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Type:
Public Security Vulnerability
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Resolution: Fixed
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Priority:
High
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Affects Version/s: 8.9.0, 8.9.1, 8.9.2, 8.9.3, 8.9.4, 9.1.0, 9.0.1, 8.9.5, 9.0.2, 9.0.3, 8.9.6, 8.9.7, 9.1.1, 8.9.8, 9.2.0, 9.2.1, 9.4.0, 9.3.1, 9.2.2, 9.3.2, 9.2.3, 9.4.1, 9.2.4, 9.2.5, 9.2.6, 9.5.1, 9.5.2, 9.5.3, 9.2.7, 10.1.0, 9.2.8, 10.0.2, 10.0.3, 9.5.4, 9.2.9, 10.1.1, 10.2.0, 9.2.10, 10.1.2, 9.2.11, 9.2.12, 10.2.1, 9.2.13, 10.2.2, 9.2.14, 10.2.3, 9.2.15, 10.2.6, 9.2.17, 10.2.7, 9.2.19, 10.2.10
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Component/s: None
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7.5
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High
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CVE-2026-34483
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Atlassian (Internal)
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CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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Confluence Data Center
This High severity Improper Encoding vulnerability known as CVE-2026-34483 was introduced in versions 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, and 10.2.0.
This Improper Encoding or Escaping of Output vulnerability, with a CVSS Score of 7.5 and a CVSS Vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N allows an unauthenticated attacker to potentially disclose sensitive information via the Apache Tomcat JsonAccessLogValve, which has high impact to confidentiality, no impact to integrity, no impact to availability, and requires no user interaction.
Atlassian recommends that Confluence Data Center and Server customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:
- Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.11
- Confluence Data Center 9.2: Upgrade to a release greater than or equal to 9.2.20
See the release notes (https://confluence.atlassian.com/doc/confluence-release-notes-327.html). You can download the latest version of Confluence Data Center and Server from the download center (https://www.atlassian.com/software/confluence/download-archives).
The National Vulnerability Database provides the following description for this vulnerability:
Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue.