High [CVE-2026-55831] Denial of Service via SPDY SETTINGS frame processing
This high-severity Red Hat Linux advisory covers CVE-2026-55831 affecting Red Hat build of Apache Camel 4.18.3 for Spring Boot 3.5.16, Red Hat Build of Apache Camel 4.18 for Quarkus 3.33, Red Hat build of Quarkus 3.27.4.SP3.
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Summary
Netty is a network application framework for development of protocol servers and clients.
Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in `DefaultSpdySettingsFrame`, allowing a remote SPDY/3.1 peer to send a syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries and amplifies network input into heap growth and ordered-map insertion work.
A remote attacker, by sending a specially crafted SPDY/3.1 SETTINGS frame, could cause the SPDY SETTINGS decoder to create a large number of map entries. This excessive processing and memory allocation can lead to a denial of service (DoS) due to heap growth and increased CPU usage.
This is an Important denial of service flaw in Netty's SPDY SETTINGS decoder, allowing a remote unauthenticated attacker to exhaust system resources. By sending a specially crafted SPDY/3.1 SETTINGS frame, an attacker can cause excessive memory allocation and CPU usage, leading to a denial of service.
This vulnerability has a low attack complexity and requires no user interaction or privileges. 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.
- < 4.1.136.Final
- < 4.2.16.Final
- < 3.1
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
- 4.1.136
- 4.2.16
- netty-codec-http
- devspaces/openvsx-rhel9:1787759145
- devspaces/pluginregistry-rhel9:1787759723
- RHSA-2026:54622
- RHSA-2026:48118
- RHSA-2026:47189
- RHSA-2026:47172
- RHSA-2026:54435
- RHSA-2026:62260
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
Mitigation checklist
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
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