{"id":"CVE-2026-59899","aliases":["GHSA-q4f6-jm68-57ww"],"url":"https://o3.security/vulnerability/CVE-2026-59899","summary":"Netty HttpContentEncoder: Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service","details":"Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, `HttpContentEncoder` (the superclass of the production handler `HttpContentCompressor`) maintains a per-channel `ArrayDeque<CharSequence>` named `acceptEncodingQueue` that accumulates attacker-controlled data without any size limit. The queue is filled on the I/O thread for every inbound HTTP request and drained only when the application later writes a non-1xx response. This creates a resource exhaustion vulnerability when an attacker exploits HTTP/1.1 pipelining to flood the connection with requests faster than the application produces responses. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.","published":"2026-07-29T18:00:37.588Z","modified":"2026-08-12T03:51:46.406232506Z","cvss":null,"epss":{"score":0.00335,"percentile":0.26343,"asOf":"2026-08-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http","fixedVersion":"4.2.16.Final"},{"ecosystem":"Maven","name":"io.netty:netty-codec-http","fixedVersion":"4.1.136.Final"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"},{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59899.json"},{"type":"ADVISORY","url":"https://github.com/netty/netty/security/advisories/GHSA-q4f6-jm68-57ww"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59899"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:46.406232506Z"}}