{"id":"CVE-2026-50009","aliases":["GHSA-cq4q-cv5g-r8q5"],"title":"Netty: QUIC stateless reset token material exposed through header-visible connection IDs","summary":"Netty: QUIC stateless reset token material exposed through header-visible connection IDs","severity":"medium","cvss":4.8,"cwe":["CWE-200","CWE-330"],"vendor":"netty","product":"io.netty:netty-codec-classes-quic","ecosystem":"maven","affected":["io.netty:netty-codec-classes-quic >= 4.2.0.Final, <= 4.2.14.Final"],"patched":["io.netty:netty-codec-classes-quic 4.2.15.Final"],"published":"2026-06-15","updated":"2026-06-15","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-cq4q-cv5g-r8q5","references":[{"url":"https://github.com/netty/netty/security/advisories/GHSA-cq4q-cv5g-r8q5"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50009"},{"url":"https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"},{"url":"https://github.com/advisories/GHSA-cq4q-cv5g-r8q5"}],"tags":["ghsa","maven"],"epss":0.00204,"epssPercentile":0.10618,"ingestedAt":"2026-07-07T15:41:58.410Z","slug":"CVE-2026-50009","body":"## Overview\n\n### Summary\nNetty QUIC exposes the stateless reset token on the network path when using the default HMAC-based connection-ID and stateless-reset-token generators. The reset token for the server's current source connection ID can be derived from bytes that appear as the connection ID in QUIC headers after a source-CID rotation. An on-path attacker observing the headers can use the token to perform a Denial of Service by sending a spoofed Stateless Reset packet.\n\n### Details\nThe sign-based connection ID generator (HmacSignQuicConnectionIdGenerator) and reset token generator (HmacSignQuicResetTokenGenerator) both evaluate HMAC-SHA256 with the same JVM-wide static key (io.netty.handler.codec.quic.Hmac).\n\nDuring source CID rotation (QuicheQuicChannel.newSourceConnectionIds), the current server source CID C is used as input to produce the next CID N. The stateless reset token for C is defined over HMAC(K, C), specifically the first 16 bytes. The next CID N is the first L bytes of the same digest, where L = |C|.\n\nWhenever L ≥ 16, the first 16 bytes of N are exactly the stateless reset token for C. Because N is carried in QUIC headers as a connection ID, an observer can read the headers and learn the reset token without decrypting the payload.\n\nThis directly violates RFC 9000\nhttps://datatracker.ietf.org/doc/html/rfc9000#name-calculating-a-stateless-res: `The stateless reset token MUST be difficult to guess.`\nAdditionally https://datatracker.ietf.org/doc/html/rfc9000#name-stateless-reset-oracle\n\n### Impact\nInformation Disclosure and Denial of Service. An on-path attacker can obtain the stateless reset token from the connection ID header and attempt to abruptly close the client side of the connection by sending a spoofed Stateless Reset datagram.\n\n## Affected packages\n\n- `io.netty:netty-codec-classes-quic >= 4.2.0.Final, <= 4.2.14.Final`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `io.netty:netty-codec-classes-quic 4.2.15.Final`","depth":"sunlit","depthScore":26,"depthScoreParts":{"impact":26.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}