CVE-2026-43403

Description

In the Linux kernel, the following vulnerability has been resolved: nsfs: tighten permission checks for ns iteration ioctls 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.

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CVSS v3.1 Score

8.8

HIGH

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

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/0ad650e60150eda789deca5e78a6a09d26bf8fc9 https://git.kernel.org/stable/c/2f3dea284c761c890d676f77d5e55c0c496b4ef4 https://git.kernel.org/stable/c/3376b345df155ca36d8611857b41ff7d5183fc38 https://git.kernel.org/stable/c/e6b899f08066e744f89df16ceb782e06868bd148

Frequently Asked Questions

What is CVE-2026-43403? +

In the Linux kernel, the following vulnerability has been resolved: nsfs: tighten permission checks for ns iteration ioctls 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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-43403? +

CVE-2026-43403 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-43403? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.