Russh: Channel-scoped server callbacks can be reached without an open channel

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS

• CVE-2026-68930: 0.38% estimated exploitation activity in the next 30 days; percentile 31.63 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

There is a server-side channel state issue in russh. After a client is authenticated, russh can dispatch channel-scoped handler callbacks for recipient channel IDs that were never opened or confirmed. In the strongest reproduced case, the client does not send SSHMSGCHANNELOPEN at all. It authenticates normally, then sends SSHMSGCHANNELREQUEST packets with request type exec for a range of recipient channel IDs. russh still calls the server application's execrequest handler. This is not an authentication bypass. A valid login is required. The issue is that the SSH channel lifecycle is not enforced before channel-scoped callbacks are delivered to the application. Impact An authenticated client can bypass the server application's channel-open policy. A server may deny session channels by returning false from Handler::channelopensession. A server may also assume that callbacks such as execrequest, shellrequest, subsystemrequest, data, channeleof, or channelclose are only delivered for…

Published by the source

3 Aug 2026, 15:35 UTC

Last modified by the source

10 Sep 2026, 03:51 UTC

Source last checked

26 Oct 2026, 15:43 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-m65r-rprj-r5rg

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-m65r-rprj-r5rg

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-68930

Advisory: Russh: Channel-scoped server callbacks can be reached without an open channel
IDs: CVE-2026-68930, GHSA-m65r-rprj-r5rg
Record: https://patchnext.com/advisories/cve-2026-68930 (revision 2, source checked 26 Oct 2026, 15:43 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: russh 0.62.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io russh: affected <= 0.62.4; fixed in 0.62.5

## Suggested inspection (read-only)
- crates.io russh: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on russh.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-m65r-rprj-r5rg (OSV record GHSA-m65r-rprj-r5rg lists affected ranges: crates.io russh >=0 <0.62.5 (fixed))
- Verified: https://github.com/advisories/GHSA-m65r-rprj-r5rg (GitHub-reviewed advisory GHSA-m65r-rprj-r5rg lists affected ranges: crates.io russh >=0 <=0.62.4)

Commands are suggestions: review each one before running it.