{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-46340: Netty: SCTP reassembly nests buffers without bound","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-46340","status":"final","version":"1","initial_release_date":"2026-06-12T14:19:48.855Z","current_release_date":"2026-06-12T16:31:09.511Z","revision_history":[{"date":"2026-06-12T14:19:48.855Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"Netty is a network application framework for development of protocol servers and clients. In versions of netty-transport-sctp prior to 4.1.135.Final and 4.2.15.Final, for each non-complete SctpMessage fragment the handler does `fragments.put(streamId, Unpooled.wrappedBuffer(frag, byteBuf))`, wrapping the previous accumulator and the new slice into a *new* CompositeByteBuf every time. After N fragments the accumulator is an N-deep chain of composites, each holding references and component arrays; readableBytes()/getBytes() on the final buffer recurse N levels. There is no limit on N, on total bytes, or on the number of streamIdentifiers an attacker can open (each gets its own map entry). A peer that never sets the `complete` flag can grow this structure indefinitely from tiny 1-byte DATA chunks. Versions 4.1.135.Final and 4.2.15.Final patch the issue.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-46340 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-46340"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-46340"},{"category":"external","summary":"https://github.com/netty/netty/security/advisories/GHSA-5xrh-qmmq-w6ch","url":"https://github.com/netty/netty/security/advisories/GHSA-5xrh-qmmq-w6ch"},{"category":"external","summary":"https://github.com/netty/netty/releases/tag/netty-4.1.135.Final","url":"https://github.com/netty/netty/releases/tag/netty-4.1.135.Final"},{"category":"external","summary":"https://github.com/netty/netty/releases/tag/netty-4.2.15.Final","url":"https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"}]},"product_tree":{"branches":[{"category":"vendor","name":"netty","branches":[{"category":"product_name","name":"netty","branches":[{"category":"product_version","name":">= 4.2.0.Final, < 4.2.15.Final","product":{"name":"netty netty >= 4.2.0.Final, < 4.2.15.Final","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"< 4.1.135.Final","product":{"name":"netty netty < 4.1.135.Final","product_id":"CSAFPID-2","product_identification_helper":{"cpe":"cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-46340","title":"Netty: SCTP reassembly nests buffers without bound","notes":[{"category":"description","text":"Netty is a network application framework for development of protocol servers and clients. In versions of netty-transport-sctp prior to 4.1.135.Final and 4.2.15.Final, for each non-complete SctpMessage fragment the handler does `fragments.put(streamId, Unpooled.wrappedBuffer(frag, byteBuf))`, wrapping the previous accumulator and the new slice into a *new* CompositeByteBuf every time. After N fragments the accumulator is an N-deep chain of composites, each holding references and component arrays; readableBytes()/getBytes() on the final buffer recurse N levels. There is no limit on N, on total bytes, or on the number of streamIdentifiers an attacker can open (each gets its own map entry). A peer that never sets the `complete` flag can grow this structure indefinitely from tiny 1-byte DATA chunks. Versions 4.1.135.Final and 4.2.15.Final patch the issue.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1","CSAFPID-2"]},"scores":[{"cvss_v3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"products":["CSAFPID-1","CSAFPID-2"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1","CSAFPID-2"]}]}]}