CVE-2021-31800: Multiple path traversal vulnerabilities exist in smbserver.py in Impacket through 0.9.22. An attacker that connects to a running smbserver instance ca...

Description

Multiple path traversal vulnerabilities exist in smbserver.py in Impacket through 0.9.22. An attacker that connects to a running smbserver instance can list and write to arbitrary files via ../ directory traversal. This could potentially be abused to achieve arbitrary code execution by replacing /etc/shadow or an SSH authorized key.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

19.26%

97.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-22

Affected Software

Vendor	Product	Versions
Secureauth	Impacket	<= 0.9.22
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34

References

Timeline

Published: May 5, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31800?

Multiple path traversal vulnerabilities exist in smbserver.py in Impacket through 0.9.22. An attacker that connects to a running smbserver instance can list and write to arbitrary files via ../ directory traversal. This could potentially be abused to achieve arbitrary code execution by replacing /etc/shadow or an SSH authorized key.

How severe is CVE-2021-31800?

CVE-2021-31800 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 19.26% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31800?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.