Vulnerability Description
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Erlang OTP (ssh_sftpd module) allows Path Traversal. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routines ssh_sftpd:is_within_root/2. The SFTP server uses string prefix matching via lists:prefix/2 rather than proper path component validation when checking if a path is within the configured root directory. This allows authenticated users to access sibling directories that share a common name prefix with the configured root directory. For example, if root is set to /home/user1, paths like /home/user10 or /home/user1_backup would incorrectly be considered within the root. This issue affects OTP from OTP 17.0 until OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Erlang | Erlang\/Otp | >= 17.0, < 26.2.5.18 |
| Erlang | Erlang\/Ssh | >= 3.0.1, < 5.1.4.14 |
Related Weaknesses (CWE)
References
- https://cna.erlef.org/cves/CVE-2026-23942.htmlVendor Advisory
- https://github.com/erlang/otp/commit/27688a824f753d4c16371dc70e88753fb410590bPatch
- https://github.com/erlang/otp/commit/5ed603a1211b83b8be2d1fc06d3f3bf30c3c9759Patch
- https://github.com/erlang/otp/commit/9e0ac85d3485e7898e0da88a14be0ee2310a3b28Patch
- https://github.com/erlang/otp/security/advisories/GHSA-4749-w85x-hw9hMitigationVendor Advisory
- https://osv.dev/vulnerability/EEF-CVE-2026-23942Vendor Advisory
- https://www.erlang.org/doc/system/versions.html#order-of-versionsProduct
FAQ
What is CVE-2026-23942?
CVE-2026-23942 is a vulnerability with a CVSS score of 5.4 (MEDIUM). Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Erlang OTP (ssh_sftpd module) allows Path Traversal. This vulnerability is associated with program file...
How severe is CVE-2026-23942?
CVE-2026-23942 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-23942?
Check the references section above for vendor advisories and patch information. Affected products include: Erlang Erlang\/Otp, Erlang Erlang\/Ssh.