CVE-2020-26299
File System Bounds Escape
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).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
File System Bounds Escape
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).
- Record
CVE-2020-26299- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
EUVDEUVD-2021-0563
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).
- Record
EUVD-2021-0563- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-pmw4-jgxx-pcq9 No score
File System Bounds Escape
Impact
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.
Background
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.
Patches
None at the moment.
Workarounds
There are no workarounds for windows servers. Hosting the server on a different OS mitigates the issue.
References
Issues: https://github.com/autovance/ftp-srv/issues/167 https://github.com/autovance/ftp-srv/issues/225
For more information
If you have any questions or comments about this advisory: Open an issue at https://github.com/autovance/ftp-srv. Please email us directly; [email protected].
- Record
GHSA-pmw4-jgxx-pcq9- Weakness
- CWE-22
- Updated
- 2026-11-02
NVD
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).
- Record
CVE-2020-26299- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N - CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N - CVSS 2.0
- 5.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
OSV
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).
- Record
CVE-2020-26299- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N - Updated
- 2026-11-02
OSVGHSA-pmw4-jgxx-pcq9 No score
File System Bounds Escape
Impact
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.
Background
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.
Patches
None at the moment.
Workarounds
There are no workarounds for windows servers. Hosting the server on a different OS mitigates the issue.
References
Issues: https://github.com/autovance/ftp-srv/issues/167 https://github.com/autovance/ftp-srv/issues/225
For more information
If you have any questions or comments about this advisory: Open an issue at https://github.com/autovance/ftp-srv. Please email us directly; [email protected].
- Record
GHSA-pmw4-jgxx-pcq9- Weakness
- CWE-22
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ftp-srvnpm |
before 4.4.0 | 4.4.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-26299 is a medium vulnerability (CVSS 6.3) in Autovance Ftp-srv, published February 10, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.89%, the 79th percentile. Fixed in ftp-srv 4.4.0.
References
npmjs.com/package/ftp-srv
github.com/autovance/ftp-srv/security/advisories/GHSA-pmw4-jgxx-pcq9
nvd.nist.gov/vuln/detail/CVE-2020-26299