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Fencer Vulns
medium 6.3

CVE-2020-26299 json

File System Bounds Escape

published 2021-02-10 5 y ago modified 2026-07-08 4 mo ago also GHSA-pmw4-jgxx-pcq9 , EUVD-2021-0563

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

ftp-srv is an open-source FTP server designed to be simple yet configurable. In ftp-srv before version 4.4.0 there is a path-traversal vulnerability. Clients of FTP servers utilizing ftp-srv hosted on Windows machines can escape the FTP user's defined root folder using the expected FTP commands, for example, CWD and UPDR. When windows separators exist within the path (`\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function. The issue is patched in version 4.4.0 (commit 457b859450a37cba10ff3c431eb4aa67771122e3).

Patch / fix

  • npm ftp-srv 4.4.0
  • ftp-srv_project ftp-srv 4.4.0

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-2020-26299 updated cvss 9.6

nodejs-ftp-srv: Path traversal in path.resolve function

  • Red Hat Openshift Container Storage 4 ocs4/mcg-core-rhel8
    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

1.89% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/autovance/ftp-srv/issues/167 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/autovance/ftp-srv/security/advisories/GHSA-pmw4-jgxx-pcq9 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/autovance/ftp-srv/issues/225 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N
NVD 3.1 9.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
NVD 2.0 5.5 AV:N/AC:L/Au:S/C:P/I:P/A:N

Affected packages

ecosystem package affected fixed in
npm ftp-srv
<4.4.0
4.4.0

Affected products

  • autovance ftp-srv

Classification

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

References

Sources

Fencer Vulns 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.