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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-08 · updated 2026-06-17

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.

Affected products

Linux kernel: from 6.19 before 6.19.9; 7.0-rc1, 7.0-rc2 — fixed in 6.19.9

How to fix

Upgrade to a fixed version: Linux kernel 6.19.9. Check the vendor advisory for mitigations.

References

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

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