CVE-2021-43566 Race condition in n/a

Low 2.5 Published Updated

A race condition in Samba allows malicious clients to create directories outside exported shares if SMB1 or NFS is enabled.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Local or same network only
Victim action needed
Not needed
Fix
Available

What is CVE-2021-43566?

CVE-2021-43566 is a low-severity vulnerability in Samba Samba, published on 11 Jan 2022. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-362

Which versions are affected by CVE-2021-43566?

It affects 1 product.

Linux distribution packages (40)
ctdb-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
libsmbclient-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
libwbclient-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
python3-samba-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-client-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-client-libs-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-common-libs-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-common-tools-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-debugsource Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-krb5-printing-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-libs-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-test-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-test-libs-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-vfs-iouring Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-vfs-iouring-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-winbind-clients-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-winbind-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-winbind-krb5-locator-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-winbind-modules-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
samba-winexe-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:4.14.5-2.el8
ctdb Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
ctdb-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
libsmbclient Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
libsmbclient-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
libwbclient Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
libwbclient-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
python3-samba Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
python3-samba-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
python3-samba-test Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-client Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-client-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-client-libs Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-client-libs-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-common Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-common-libs Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-common-libs-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-common-tools Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8
samba-common-tools-debuginfo Red Hat:enterprise_linux:8::baseosAll versions0:4.14.5-2.el8

Products include Samba Samba.

How do I fix CVE-2021-43566?

Upgrade to a fixed version.

Is CVE-2021-43566 being exploited?

There is no known exploitation of CVE-2021-43566 in the wild and no public exploit code.

All Samba Samba vulnerabilities

Sources

Also known as ALPINE-CVE-2021-43566, AZL-37006, AZL-7489, CLSA-2026-1780064574, CLSA-2026-1780070780, CLSA-2026-1780134251 and 6 more.

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