Linux Distros Unpatched Vulnerability : CVE-2026-53422

low Nessus Plugin ID 324937

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- Observable Response Discrepancy vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated SFTP user to enumerate the existence of files and directories outside the configured root directory. The SSH_FXP_REALPATH handler in ssh_sftpd calls relate_file_name/3 with Canonicalize=false, unlike every other SFTP operation handler. This allows .. components in the requested path to bypass the is_within_root/2 check without being resolved. The un-canonicalized path then enters resolve_symlinks/2, which walks up the directory tree above the configured root and issues read_link() syscalls on arbitrary filesystem paths. An authenticated SFTP client can exploit this by sending a REALPATH request with a crafted traversal path.
The server response differs depending on whether the target path exists on the host filesystem (SSH_FXP_NAME when the path resolves successfully, SSH_FX_NO_SUCH_FILE when it does not). This creates a path-existence oracle that an attacker can use to enumerate the filesystem structure outside the configured root, including the existence of sensitive files, directories, and mount points. The vulnerability leaks only the existence of paths. No file contents, credentials, or write access are obtainable through this issue alone. The information gained may assist further attacks when combined with other vulnerabilities. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routine ssh_sftpd:handle_op/4. This issue affects OTP from OTP 17.0 until OTP 29.0.3, 28.5.0.3, and 27.3.4.14 corresponding to ssh from 3.0.1 until 6.0.2, 5.5.2.2, and 5.2.11.9. (CVE-2026-53422)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Low

ID: 324937

File Name: unpatched_CVE_2026_53422.nasl

Version: 1.2

Type: Local

Agent: unix

Family: Misc.

Published: 7/3/2026

Updated: 7/4/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.2

Percentile: 51.07

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:N/A:N

CVSS Score Source: CVE-2026-53422

CVSS v3

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 4

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C

CVSS v4

Risk Factor: Low

Base Score: 2.3

Threat Score: 0.6

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:debian:debian_linux:11.0, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:debian:debian_linux:erlang, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:erlang, cpe:/o:debian:debian_linux:13.0, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:debian:debian_linux:14.0, cpe:/o:debian:debian_linux:12.0, cpe:/o:canonical:ubuntu_linux:26.04:-:lts

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 7/2/2026

Reference Information

CVE: CVE-2026-53422

Detections

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