Russh: Channel-scoped server callbacks can be reached without an open channel
Priority MEDIUM 62CWE-666Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-863.
Summary
Russh is a Rust SSH client & server library. Prior to 0.62.5, russh dispatches channel-scoped Handler callbacks for recipient channel IDs that were never opened or confirmed in russh/src/server/encrypted.rs, server_read_authenticated, and the exec_request callback. Version 0.62.5 fixes the issue.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00376 31st percentileScored 2026-11-07
Fix Fixed russh (Eugeny): 0.62.5russh (crates.io): 0.62.5
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Eugeny | russh | before 0.62.5 | 0.62.5 | Patch available | CNA |
| — | russh (crates.io) | before 0.62.5 | 0.62.5 | Patch available | GHSA-m65r-rprj-r5rg |
- russh VendorEugeny Affected before 0.62.5 Fixed in 0.62.5 Patch available CNA
- russh (crates.io) Vendor— Affected before 0.62.5 Fixed in 0.62.5 Patch available GHSA-m65r-rprj-r5rg
Remediation
- Fix · CNA russh (Eugeny) Fixed in 0.62.5
- Fix · GHSA-m65r-rprj-r5rg russh (crates.io) Fixed in 0.62.5 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-68930
- 2026-10-03 Alias added: GHSA-m65r-rprj-r5rg
References
More Eugeny vulnerabilities
- TI-2026-65512 russh: Client-side channel-scoped Handler callbacks fire for channel IDs the client never opened CVSS 3.1HIGH 7.5
- TI-2026-35550 Russh: SSH message fields were decoded through allocation-first parsers before field-specific bounds CVSS 3.1HIGH 7.5
- TI-2026-34331 Russh: Post-decompression SSH packet size was not bounded, allowing remote oversized compressed packets CVSS 3.1HIGH 7.5
- TI-2026-34308 Resource allocation without limits in Eugeny russh CVSS 3.1HIGH 7.5
- TI-2025-16084 Tabby has a TCC Bypass via Misconfigured Node Fuses CVSS 4.0HIGH 8.6
- TI-2024-36991 Tabby has a TCC Bypass via Unnecessary Permissive Entitlements in Tabby CVSS 4.0HIGH 8.6
Sources
- CVE-2026-68930 · CVE Program
- CVE-2026-68930 · NVD
- FIRST EPSS
- GHSA-m65r-rprj-r5rg · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences