CVE-2026-55833High· 7.5▾ TwilightA flaw was found in Netty, a network application framework. A remote attacker could exploit a vulnerability in the SPDY header decoding process. By sending a specially crafted, small compressed header block, the attacker can cause it to ex…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 31.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CSAF
0.4%
0.4% → 0.7%
Last analysed / modified upstream
A flaw was found in Netty, a network application framework. A remote attacker could exploit a vulnerability in the SPDY header decoding process. By sending a specially crafted, small compressed header block, the attacker can cause it to expand significantly during decompression, leading to excessive CPU usage and memory allocation. This can result in a denial of service (DoS) due to resource exhaustion.
netty: io.netty/netty-codec-http: Netty: Denial of Service via SPDY header decompression amplification — rated Important by Red Hat. Released 2026-07-20, updated 2026-10-20.
Affected:
Fixed:
No fix planned:
Not affected:
Before applying the update, make sure all previously released errata relevant to your system have been applied. Also, back up your existing installation, including all applications, configuration files, databases and database settings. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:70230 Before applying the update, make sure all previously released errata relevant to your system have been applied. Also, back up your existing installation, including all applications, configuration files, databases and database settings. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:70228 Before applying this update, make sure all previously released errata relevant to your system have been applied.
For details on how to apply this update, refer to:
https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:68333
Workarounds / mitigations:
Affected packages:
io.netty:netty-codec-http >= 4.2.0.Final, <= 4.2.15.Finalio.netty:netty-codec-http >= 4.1.0.Final, <= 4.1.135.FinalPatched in:
io.netty:netty-codec-http 4.2.16.Finalio.netty:netty-codec-http 4.1.136.FinalConnected by shared product, vendor, weakness, or advisory.
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