CVE-2026-56819: Atlassian DoS (Denial of Service) io.netty:netty-codec-http2 Dependency in Confluence Data Center
This Atlassian advisory covers CVE-2026-56819 in Confluence Data Center and Server.
Key facts
- Vendor rating
- High, CVSS 7.5
- CISA KEV
- Not listed (catalogue checked )
- Affected
- Confluence Data Center and Server: 10.2.0 to 10.2.15 (LTS); Confluence Data Center and Server: 10.1.0 to 10.1.2; Confluence Data Center and Server: 10.0.2 to 10.0.3 and 8 more below
- Fixed in
- Confluence Data Center and Server: 10.2.17 to 10.2.18 (LTS) recommended Data Center Only, Confluence Data Center and Server: 9.2.24 to 9.2.25 (LTS) Data Center Only
- Source published
- Listed by VulniPulse
Compiled by VulniPulse from the linked sources. How records are collected and checked.
Affected products & platforms
Description
DoS (Denial of Service) io.netty:netty-codec-http2 Dependency in Confluence Data Center. Affected: Confluence Data Center and Server.
Listed in Atlassian's Security Bulletin of September 15 2026.
Text from the source record.
- Confluence Data Center and Server: 10.2.0 to 10.2.15 (LTS)
- Confluence Data Center and Server: 10.1.0 to 10.1.2
- Confluence Data Center and Server: 10.0.2 to 10.0.3
- Confluence Data Center and Server: 9.5.1 to 9.5.4
- Confluence Data Center and Server: 9.4.0 to 9.4.1
- Confluence Data Center and Server: 9.3.1 to 9.3.2
- Confluence Data Center and Server: 9.2.0 to 9.2.23 (LTS)
- Confluence Data Center and Server: 9.1.0 to 9.1.1
- Confluence Data Center and Server: 8.9.7 to 8.9.8
- Confluence Data Center and Server: 8.5.16 to 8.5.31 (LTS)
- Confluence Data Center and Server: 7.19.28 to 7.19.30 (LTS)
Official advisory · high-confidence parse· fetched ·verify at source
How to fix CVE-2026-56819
Upgrade to a fixed release named by Atlassian:
- Confluence Data Center and Server: 10.2.17 to 10.2.18 (LTS) recommended Data Center Only
- Confluence Data Center and Server: 9.2.24 to 9.2.25 (LTS) Data Center Only
Vendor guidance
- Upgrade to a fixed version listed by Atlassian: Confluence Data Center and Server: 10.2.17 to 10.2.18 (LTS) recommended Data Center Only; Confluence Data Center and Server: 9.2.24 to 9.2.25 (LTS) Data Center Only.
Support dates for the fixed release lines
- Atlassian Confluence 10.2: support ends
- Atlassian Confluence 9.2: support ends
CVE-2026-56819 in other vendors' advisories
- NetApp: NTAP-20260917-0005
- Red Hat: CVE-2026-56819, high severity, fixed in 4.1.136, 4.2.16, cryostat/cryostat-reports-rhel9:4.2.0-14 and 33 more
More Atlassian advisories
CVE-2026-75595Oct 20, 2026BASM (Broken Authentication & Session Management) io.netty:netty-handler DependencyCVE-2026-73646Oct 20, 2026Path Traversal (Arbitrary Read/Write) postcss Dependency in Confluence Data CenterCVE-2026-73508Oct 20, 2026DoS (Denial of Service) io.netty:netty-codec-dns Dependency in Bitbucket Data CenterCVE-2026-68763Oct 20, 2026DoS (Denial of Service) org.apache.tomcat:tomcat-coyote Dependency in Confluence DataCVE-2026-68569Oct 20, 2026BASM (Broken Authentication & Session Management) org.apache.tomcat:tomcat-catalinaCVE-2026-68525Oct 20, 2026Improper Authorization org.apache.tomcat:tomcat-catalina Dependency in Confluence Data
Atlassian advisories, September 2026All Atlassian advisories
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