High [CVE-2026-5680] Undertow-core: undertow: denial of service via websocket permessage-deflate processing
This high-severity Red Hat Linux advisory covers CVE-2026-5680 affecting Red Hat build of Apache Camel for Spring Boot 4, Red Hat Data Grid 8, Red Hat Enterprise Linux 10.
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Summary
A flaw was found in Undertow. A remote attacker could exploit this vulnerability by sending specially crafted WebSocket messages with permessage-deflate negotiated.
This could lead to excessive memory consumption due to the PerMessageDeflateFunction.largerBuffer() method using exponential doubling, resulting in a Denial of Service (DoS) for the affected application. Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-770.
Affected Red Hat products: Red Hat build of Apache Camel for Spring Boot 4; Red Hat Data Grid 8; Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Fuse 7; Red Hat JBoss Enterprise Application Platform 7; Red Hat JBoss Enterprise Application Platform 8; Red Hat JBoss Enterprise Application Platform Expansion Pack; Red Hat Process Automation 7; Red Hat Single Sign-On 7.
Will not fix / out of support: Red Hat JBoss Enterprise Application Platform 7; Red Hat Process Automation 7; Red Hat Single Sign-On 7. Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: moditect-javadoc; Red Hat package: moditect.src; Red Hat package: pki-resteasy-client; Red Hat package: pki-resteasy-core; and 2 more.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- To mitigate this issue, configure the PerMessageDeflateHandshake to limit the maximum decompressed buffer size. This can be achieved by setting the maxDecompressedBufferSize parameter to a reasonable value (e.g., 10 MB) in the PerMessageDeflateHandshake constructor. This action may require a restart of the affected application or service to take effect.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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