CVE-2015-3644

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.

Published: 2015-05-14 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-3644 is rated Low Risk (34.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.16%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2015-3644

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-30 0.56% 0.16% -0.41%
2 2025-03-29 0.16% 0.56% +0.41%
3 2025-03-17 — 0.16% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-3644

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2015-3644

OS Trackers for CVE-2015-3644

vendor priority summary link
debian not yet assigned CVE-2015-3644 not yet assigned priority: Debian including 1 source packages (stunnel4), 4 status rows across 4 suites (bookworm, bullseye, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2015-3644
redhat high — https://access.redhat.com/security/cve/CVE-2015-3644
suse medium CVE-2015-3644 severity moderate: SUSE including 9 source package names (stunnel, stunnel-5.00-3.1, …), 19 product×package rows across 17 product lines (SUSE Linux Enterprise High Performance Computing 12 SP5, SUSE Linux Enterprise Module for Server Applications 15 SP5, … (17 product lines)): Fixed 16, Known Not Affected 3. https://www.suse.com/security/cve/CVE-2015-3644/
ubuntu medium CVE-2015-3644 medium priority: Ubuntu including 1 source packages (stunnel4), 12 status rows across 12 suites (artful, bionic, cosmic, precise, trusty, upstream, utopic, vivid, wily, xenial, yakkety, zesty): not-affected 8, ignored 2, released 2. https://ubuntu.com/security/CVE-2015-3644

Affected software / configurations for CVE-2015-3644

Vendor Product Version Raw CPE
stunnel stunnel 5.00 cpe:2.3:a:stunnel:stunnel:5.00:*:*:*:*:*:*:*
stunnel stunnel 5.01 cpe:2.3:a:stunnel:stunnel:5.01:*:*:*:*:*:*:*
stunnel stunnel 5.02 cpe:2.3:a:stunnel:stunnel:5.02:*:*:*:*:*:*:*
stunnel stunnel 5.03 cpe:2.3:a:stunnel:stunnel:5.03:*:*:*:*:*:*:*
stunnel stunnel 5.04 cpe:2.3:a:stunnel:stunnel:5.04:*:*:*:*:*:*:*
stunnel stunnel 5.05 cpe:2.3:a:stunnel:stunnel:5.05:*:*:*:*:*:*:*
stunnel stunnel 5.06 cpe:2.3:a:stunnel:stunnel:5.06:*:*:*:*:*:*:*
stunnel stunnel 5.07 cpe:2.3:a:stunnel:stunnel:5.07:*:*:*:*:*:*:*
stunnel stunnel 5.08 cpe:2.3:a:stunnel:stunnel:5.08:*:*:*:*:*:*:*
stunnel stunnel 5.09 cpe:2.3:a:stunnel:stunnel:5.09:*:*:*:*:*:*:*
stunnel stunnel 5.10 cpe:2.3:a:stunnel:stunnel:5.10:*:*:*:*:*:*:*
stunnel stunnel 5.11 cpe:2.3:a:stunnel:stunnel:5.11:*:*:*:*:*:*:*
stunnel stunnel 5.12 cpe:2.3:a:stunnel:stunnel:5.12:*:*:*:*:*:*:*
stunnel stunnel 5.13 cpe:2.3:a:stunnel:stunnel:5.13:*:*:*:*:*:*:*

References for CVE-2015-3644

cvelogic Threat Intelligence