CVE-2021-43566

Severity: low (CVSS 2.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-01-11 · updated 2026-06-17
Weakness: CWE-362

Description

All versions of Samba prior to 4.13.16 are vulnerable to a malicious client using an SMB1 or NFS race to allow a directory to be created in an area of the server file system not exported under the share definition. Note that SMB1 has to be enabled, or the share also available via NFS in order for this attack to succeed.

Affected products

Samba: before 4.13.16 — fixed in 4.13.16

How to fix

Upgrade to a fixed version: Samba 4.13.16. Check the vendor advisory for mitigations.

References

https://bugzilla.samba.org/show_bug.cgi?id=13979
https://security.netapp.com/advisory/ntap-20220110-0001/
https://www.samba.org/samba/security/CVE-2021-43566.html
https://bugzilla.samba.org/show_bug.cgi?id=13979
https://security.netapp.com/advisory/ntap-20220110-0001/
https://www.samba.org/samba/security/CVE-2021-43566.html

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