Netty SPDY zlib header block continues decoded expansion after maxHeaderSize truncation
CVSS v3
7.5
HIGH
EPSS Score
—
exploit probability
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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 i
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 i
Active exploitation of CVE-2026-55833 has not been confirmed. The EPSS score is N/A%, indicating the estimated probability of exploitation in the next 30 days.
CVE-2026-55833 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string 3.1.
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