Detections
Analytics

Linux Distros Unpatched Vulnerability : CVE-2025-15661

high Nessus Plugin ID 321796

Language:

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.

 - libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() function in src/sftp.c that allows a malicious SSH server or man-in-the-middle attacker to disclose heap memory contents or cause a crash by sending a crafted SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation. (CVE-2025-15661)

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

Solution

There is no known solution at this time.

See Also

https://security-tracker.debian.org/tracker/CVE-2025-15661

https://ubuntu.com/security/CVE-2025-15661

Plugin Details

Severity: High

ID: 321796

File Name: unpatched_CVE_2025_15661.nasl

Version: 1.9

Type: Local

Agent: unix

Family: Misc.

Published: 6/20/2026

Updated: 7/10/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.5

Percentile: 52

CVSS v2

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 5.2

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:N/A:C

CVSS Score Source: CVE-2025-15661

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 6

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

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

CVSS v4

Risk Factor: High

Base Score: 8.3

Threat Score: 4.8

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/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, p-cpe:/a:debian:debian_linux:libssh2, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libssh2, cpe:/o:debian:debian_linux:12.0

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 6/18/2026

Reference Information

CVE: CVE-2025-15661