Log in Start free

Vulnerability · Published Mar 13, 2026 · Assigned by EEF

CVE-2026-23942SFTP root escape via component-agnostic prefix check in ssh_sftpd

Medium 5.3

In plain English

A medium-severity path traversal in OTP from Erlang. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.3Medium
Exploit odds (30 days)0.4%top 67.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12erlang1:25.2.3+dfsg-1+deb12u4DEBIAN-CVE-2026-23942
Debian:13erlang1:27.3.4.1+dfsg-1+deb13u2DEBIAN-CVE-2026-23942
Debian:14erlang1:27.3.4.9+dfsg-1DEBIAN-CVE-2026-23942
Ubuntu:22.04:LTSerlang1:24.2.1+dfsg-1ubuntu0.8USN-8901-1
Ubuntu:22.04:LTSerlang1:24.2.1+dfsg-1ubuntu0.8UBUNTU-CVE-2026-23942
Ubuntu:24.04:LTSerlang1:25.3.2.8+dfsg-1ubuntu4.8USN-8901-1
Ubuntu:24.04:LTSerlang1:25.3.2.8+dfsg-1ubuntu4.8UBUNTU-CVE-2026-23942
Ubuntu:25.10erlangno fix listedUBUNTU-CVE-2026-23942
Ubuntu:26.04:LTSerlang1:27.3.4.6+dfsg-1ubuntu0.2UBUNTU-CVE-2026-23942
Ubuntu:26.04:LTSerlang1:27.3.4.6+dfsg-1ubuntu0.2USN-8901-1

Affected products (as reported)

VendorProductVersions
Erlang OTP 3.0.1 – before *
Erlang OTP 17.0 – before *84adefa331c4159d432d22840663c38f155cd4c1 – before *

Weakness: CWE-22 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References