CVE-2026-109438

MEDIUM 5.3

3proxy 0.9.7 - 1.0.1 Uninitialized Stack Memory Disclosure via SOCKS4

CVSS Score

5.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-908
Vendor	3proxy
Product	3proxy
Published	Oct 14, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Affected Versions

3proxy / 3proxy

0.9.7 ≤ 1.0.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/3proxy/3proxy/commit/206c923d6cd433bd2e7196375442650c328b8bfa vulncheck.com: https://www.vulncheck.com/advisories/3proxy-uninitialized-stack-memory-disclosure-via-socks4

Credits

Sam Barker of VulnCheck