CVE-2020-26299

File System Bounds Escape

CRITICAL
9.6
CVSS Score
Published: February 10, 2021 at 06:10 PM UTC
Updated: June 17, 2026 at 03:08 AM UTC
2 products affected across 2 vendorsFTP SrvSrv Project FTP Srv

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Severity
CRITICAL9.6
Exploit prediction
EPSS 2%

Description

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).

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.4.0
Affected range stops below 4.4.0, so it looks safe — our inference, not a vendor statement
v < 4.4.0
Affected range stops below 4.4.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (6)

x_refsource_MISCExploitPatchThird Party Advisory
https://github.com/autovance/ftp-srv/issues/167
x_refsource_MISCExploitThird Party Advisory
https://github.com/autovance/ftp-srv/issues/225
x_refsource_MISCPatchThird Party Advisory
https://github.com/autovance/ftp-srv/pull/224
x_refsource_MISCProductThird Party Advisory
https://www.npmjs.com/package/ftp-srv

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-22

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