{"cve":"CVE-2026-46340","nvd":{"published":"2026-06-12T15:16:27.743","modified":"2026-09-18T13:18:27.540","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-770"],"references":["https://github.com/netty/netty/releases/tag/netty-4.1.135.Final","https://github.com/netty/netty/releases/tag/netty-4.2.15.Final","https://github.com/netty/netty/security/advisories/GHSA-5xrh-qmmq-w6ch","https://access.redhat.com/errata/RHSA-2026:37390","https://access.redhat.com/errata/RHSA-2026:41951"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-19T22:38:48.522727527+00:00"},"epss":{"cve":"CVE-2026-46340","score":0.00606,"percentile":0.49018,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-5xrh-qmmq-w6ch","url":"https://osv.dev/vulnerability/GHSA-5xrh-qmmq-w6ch","summary":"Netty: SCTP reassembly nests buffers without bound","modified":"2026-09-10T03:50:48.440058574Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-transport-sctp","purl":"pkg:maven/io.netty/netty-transport-sctp","ranges":[">=4.2.0.Final <4.2.15.Final"],"fixed":["4.2.15.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-transport-sctp","purl":"pkg:maven/io.netty/netty-transport-sctp","ranges":["<4.1.135.Final"],"fixed":["4.1.135.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}