CVE-2026-55833
Netty SPDY zlib header block continues decoded expansion after maxHeaderSize truncation
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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 SPDY header decoding continues inflating zlib-compressed header blocks after the raw header parser has exceeded `maxHeaderSize` and marked the frame truncated in `SpdyFrameCodec`, allowing a remote peer to send a small compressed `HEADERS` block that expands into much larger raw header data and causes compression-amplified CPU and allocation churn. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
| CWE | CWE-400 |
| Vendor | netty |
| Product | netty |
| Published | Jul 20, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
netty / netty
>= 4.2.0.Final, < 4.2.16.Final >= 4.1.0.Final, < 4.1.136.Final
References
github.com: https://github.com/netty/netty/security/advisories/GHSA-mvh2-crg5-v77c github.com: https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b github.com: https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 github.com: https://github.com/netty/netty/releases/tag/netty-4.1.136.Final github.com: https://github.com/netty/netty/releases/tag/netty-4.2.16.Final