{"id":"CVE-2026-55833","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-55833","generatedAt":"2026-10-28T01:43:51.824Z","title":"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…","description":"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.","published":"2026-07-21T00:17:36.000Z","lastModified":"2026-07-23T13:34:45.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-400"],"affected":["netty/netty"],"epss":{"score":0.00665,"percentile":0.51516,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.66%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/netty/netty/security/advisories/GHSA-mvh2-crg5-v77c","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-55833","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}