Is CVE-2015-3644 in the CISA KEV catalog?

No. CVE-2015-3644 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2015-3644?

CVE-2015-3644 has a CVSS v2 base score of 5.8 (MEDIUM).

What is the EPSS score for CVE-2015-3644?

CVE-2015-3644 has an EPSS score of 2.14% (80th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2015-3644?

Upgrade stunnel4 on debian 11 to 3:5.18-1 or later.

CVE & CISA-KEV Catalog

CVE-2015-3644

MEDIUMEPSS 80th pctl

5.8

CVSS v2

NVD

Description

Stunnel 5.00 through 5.13, when using the redirect option, does not redirect client connections to the expected server after the initial connection, which allows remote attackers to bypass authentication.

CWE-284Improper Access Control

How to fix

Remediation Available

stunnel4Debian

Fixed in:3:5.18-1CVE-2015-3644

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

2.14%probability of exploitation in 30 days

80thpercentile

Elevated risk: more likely to be exploited than 80% of all known CVEs.

References

Patch1

stunnel.org

Other references3

Related Vulnerabilities

Other CWE-284 (Improper Access Control) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-27350	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2019-1653	High	7.5	100%	KEV	-
CVE-2023-23752	Medium	5.3	100%	KEV	Fix
CVE-2023-29298	High	7.5	100%	KEV	-
CVE-2023-38205	High	7.5	100%	KEV	-
CVE-2024-27348	Critical	9.8	99%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-06.