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Medium severity · published Mar 13, 2026
CVE-2026-23942
SFTP root escape via component-agnostic prefix check in ssh_sftpd
5.4
CVSS
0.4%
EPSS
No
On KEV
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 before OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to ssh from 3.0.1 before 5.5.1, 5.2.11.6 and 5.1.4.14.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OT
OTP · Erlang
3.0.1; 17.0; 84adefa331c4159d432d22840663c38f155cd4c1 · source: vendor
ER
Erlang/otp · Erlang
17.0 before 26.2.5.18; 27.0 before 27.3.4.9; 28.0 before 28.4.1 · source: NVD
ER
Erlang/ssh · Erlang
3.0.1 before 5.1.4.14; 5.2 before 5.2.11.6; 5.5 through 5.5.1 · source: NVD
Affected product
OT
OTP
Erlang
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23942
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-23942
Vendor Advisory
https://cna.erlef.org/cves/CVE-2026-23942.html
Patch
https://github.com/erlang/otp/commit/27688a824f753d4c16371dc70e88753fb410590b
Patch
https://github.com/erlang/otp/commit/5ed603a1211b83b8be2d1fc06d3f3bf30c3c9759
Patch
https://github.com/erlang/otp/commit/9e0ac85d3485e7898e0da88a14be0ee2310a3b28
Mitigation
https://github.com/erlang/otp/security/advisories/GHSA-4749-w85x-hw9h
Vendor Advisory
https://osv.dev/vulnerability/EEF-CVE-2026-23942
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