What is CVE-2021-20316?

CVE-2021-20316 is a medium-severity vulnerability in Samba, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 6.8/10. Published 2022-08-23.

How severe is CVE-2021-20316?

Medium severity. CVSS v3 base score is 6.8 out of 10.

Is CVE-2021-20316 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Samba

CVE-2021-20316

A flaw was found in the way Samba handled file/directory metadata. This flaw allows an authenticated attacker with permissions to read or modify share metadata, to perform this operation outside of the share.

Vulnerability class: Race Condition

Published 2022-08-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.010 (63.5th percentile), scored 2026-10-20.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: +0.001

Affected products

Samba
Debian Linux — versions 10.0, 11.0
Red Hat Enterprise Linux — versions 8.0
Red Hat Enterprise Linux Aus — versions 8.6
Red Hat Enterprise Linux Eus — versions 8.6
Red Hat Enterprise Linux Tus — versions 8.6
Red Hat Virtualization Host — versions 4.0
Samba — versions Affects samba file server before v4.15.0, Fixed in samba v4.15.0

Weakness classification (CWE)

CWE-362 — Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

bugzilla.samba.org/show_bug.cgi (Issue Tracking, Vendor Advisory)
www.samba.org/samba/security/CVE-2021-20316.html (Vendor Advisory)
bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
access.redhat.com/security/cve/CVE-2021-20316 (Third Party Advisory)
security-tracker.debian.org/tracker/CVE-2021-20316 (Third Party Advisory, Mitigation)
security.gentoo.org/glsa/202309-06 (vendor-advisory)

Frequently asked questions

What is CVE-2021-20316?: CVE-2021-20316 is a medium-severity vulnerability in Samba, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 6.8/10. Published 2022-08-23.
How severe is CVE-2021-20316?: Medium severity. CVSS v3 base score is 6.8 out of 10.
Is CVE-2021-20316 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.