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Fencer Intel
critical 9.8

CVE-2021-31800 in the critical feed json

Path traversal in impacket

published 5y ago modified 4mo ago also GHSA-mj63-64x7-57xf , PYSEC-2021-17 , EUVD-2021-0100

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
19.4%
EPSS 19.4% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi impacket 0.9.23
  • impacket Debian 14, Debian 13, Debian 12 0.9.22-2

debian advisories DEBIAN-CVE-2021-31800

  • python-impacket openSUSE Tumbleweed 0.13.1-1.2
  • python-impacket openSUSE Tumbleweed 0.11.0-3.3

opensuse advisories openSUSE-SU-2026:12011-1openSUSE-SU-2024:14142-1

  • py3-impacket Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 0.9.23-r0

alpine advisories ALPINE-CVE-2021-31800

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • impacket Arch Linux 0.9.23-1

arch linux advisories AVG-1916

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-31800 updated cvss 8.1

python-impacket: Multiple path traversal vulnerabilities in smbserver.py

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

19.41% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi impacket
<0.9.23
>=0.9.10, <0.9.23
0.9.23

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.