{"id":"CVE-2026-102821","summary":"Russh: Unbounded memory exhaustion via CHANNEL_OPEN flood during a client-stalled rekey","details":"Russh is a Rust SSH client and server library. Prior to 0.63.2, an authenticated remote peer can send SSH_MSG_KEXINIT without the required SSH_MSG_KEX_ECDH_INIT and then flood SSH_MSG_CHANNEL_OPEN messages while SessionKexState::InProgress prevents priority_receiver in russh/src/server/session.rs from being drained. The server continues processing network input and enqueues a ChannelOpenReply for each request on an unbounded channel, allowing one connection to grow memory until the process is terminated. This issue is fixed in version 0.63.2.","aliases":["GHSA-35g8-35p8-c8fw"],"modified":"2026-09-30T03:47:23.566184045Z","published":"2026-09-29T18:21:21.858Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-400","CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102821.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102821.json"},{"type":"FIX","url":"https://github.com/Eugeny/russh/commit/a282af361ac99bc76b80876d1aae128e89dbf66b"},{"type":"WEB","url":"https://github.com/Eugeny/russh/releases/tag/v0.63.2"},{"type":"ADVISORY","url":"https://github.com/Eugeny/russh/security/advisories/GHSA-35g8-35p8-c8fw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-102821"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/eugeny/russh","events":[{"introduced":"0"},{"fixed":"8a51a0dca4f6fbdcc3ce98c627254026b25b3252"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"0.63.2"}]}}],"versions":["v0.63.1","v0.63.0","v0.63.0-beta.1","v0.62.7","v0.62.6","v0.62.5","v0.62.4","v0.62.3","v0.62.2","v0.62.1","v0.62.0","v0.61.2","v0.61.1","v0.61.0","v0.60.3","v0.60.2","v0.60.1","v0.60.0","v0.59.0","v0.58.0","v0.57.1","v0.57.0","v0.56.0","v0.55.0","v0.54.6","v0.54.5","v0.54.4","v0.54.3","v0.54.2","v0.54.1","v0.54.0","v0.53.0","v0.53.0-beta.1","v0.52.1","v0.52.0","v0.52.0-beta.1","v0.51.1","v0.51.0","v0.51.0-beta.3","v0.51.0-beta.2","v0.51.0-beta.1","v0.50.4","v0.50.3","v0.50.1","v0.50.0","v0.50.0-beta.12","v0.50.0-beta.11","v0.50.0-beta.10","v0.50.0-beta.9","v0.50.0-beta.8","v0.50.0-beta.7","v0.50.0-beta.6","v0.50.0-beta.5","v0.50.0-beta.4","v0.50.0-beta.3","v0.50.0-beta.2","v0.49.0","v0.48.2","v0.48.1","v0.48.0","v0.47.0-beta.4","v0.47.0-beta.3","v0.46.0","v0.45.0","v0.44.0","v0.44.0-beta.4","v0.44.0-beta.3","v0.44.0-beta.1","v0.43.0","v0.43.0-beta.1","v0.42.0","v0.40.2","v0.40.1","v0.40.0","v0.38.0","v0.39.0-beta.1","v0.38.0-beta.1","v0.37.1","v0.37.0","v0.36.1","v0.37.0-beta.1","0.37.0-beta.1","v0.35.0-beta.9","v0.35.0-beta.8","v0.35.0-beta.7","v0.35.0-beta.6","v0.35.0-beta.5","v0.35.0-beta.3","v0.35.0-beta.2","v0.35.0-beta.1","v0.34.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-102821.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}