{"id":"CVE-2026-59899","state":"PUBLISHED","title":"Netty HttpContentEncoder: Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service","description":"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.","publishedAt":"2026-07-29T18:00:37.588Z","updatedAt":"2026-07-30T14:01:48.362Z","severity":{"score":6.9,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["netty netty"],"affected":[{"vendor":"netty","product":"netty","versions":[{"version":">= 4.2.0.Final, < 4.2.16.Final","status":"affected"},{"version":"< 4.1.136.Final","status":"affected"}]}],"references":["https://github.com/netty/netty/security/advisories/GHSA-q4f6-jm68-57ww","https://github.com/netty/netty/releases/tag/netty-4.1.136.Final","https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"],"weaknesses":["CWE-770"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/59xxx/CVE-2026-59899.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59899","state":"PUBLISHED","datePublished":"2026-07-29T18:00:37.588Z","dateUpdated":"2026-07-30T14:01:48.362Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-07T16:40:07.984Z"},"containers":{"cna":{"title":"Netty HttpContentEncoder: Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"netty","product":"netty","versions":[{"version":">= 4.2.0.Final, < 4.2.16.Final","status":"affected"},{"version":"< 4.1.136.Final","status":"affected"}]}],"references":[{"url":"https://github.com/netty/netty/security/advisories/GHSA-q4f6-jm68-57ww","name":"https://github.com/netty/netty/security/advisories/GHSA-q4f6-jm68-57ww","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final","name":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final","tags":["x_refsource_MISC"]},{"url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final","name":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-29T18:00:37.588Z"},"source":{"advisory":"GHSA-q4f6-jm68-57ww","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-30T14:01:28.204351Z","id":"CVE-2026-59899","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-30T14:01:48.362Z"}}]}}}