CVE-2026-109438 MEDIUM

CVE-2026-109438: 3proxy 0.9.7 - 1.0.1 Uninitialized Stack Memory Disclosure via SOCKS4

Vendor 3Proxy
Product 3proxy
Weakness CWE-908
Published October 14, 2026
Last update October 27, 2026

CVSS base score

6.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

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

What the vulnerability does

01Description

3proxy from 0.9.7 through 1.0.1, fixed in commit 206c923, contains an uninitialized stack memory disclosure vulnerability that allows unauthenticated attackers to leak stack bytes via the SOCKS4 reply path when the external-NAT option (-Ne) is configured. Attackers can send a client probe that fails the SOCKS version check to trigger a reply containing uninitialized bytes from the sin structure, exposing high bytes of a userspace pointer that weakens ASLR protections.

Key dates

02Disclosure timeline

October 14, 2026 CVE published
October 27, 2026 Record updated