CVE-2026-102821Russh: Unbounded memory exhaustion via CHANNEL_OPEN flood during a client-stalled rekey
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-400, CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Sep 30, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Eugeny russh eugeny:russh (from the name) | before 0.63.2 | CNA record |
References
- https://github.com/Eugeny/russh/security/advisories/GHSA-35g8-35p8-c8fwx-refsource-confirm
- https://github.com/Eugeny/russh/commit/a282af361ac99bc76b80876d1aae128e89dbf66bx-refsource-misc
- https://github.com/Eugeny/russh/releases/tag/v0.63.2x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.