Stunnel 5.00 through 5.13, when using the redirect option, does not redirect client…
Priority LOW 30CWE-284Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- — Not recorded in CVSS 2.0
- Attack complexity
- Medium
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Partial · Partial · None
- Fix status
- No fix listed
Attack profile from CVSS 2.0 · NVD. Fix status from CNA. Impact type from CWE-284.
Summary
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.
Why it matters now
EPSS 0.0212 81st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 14
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:stunnel:stunnel:5.00:*:*:*:*:*:*:* | 5.00 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.01:*:*:*:*:*:*:* | 5.01 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.02:*:*:*:*:*:*:* | 5.02 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.03:*:*:*:*:*:*:* | 5.03 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.04:*:*:*:*:*:*:* | 5.04 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.05:*:*:*:*:*:*:* | 5.05 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.06:*:*:*:*:*:*:* | 5.06 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.07:*:*:*:*:*:*:* | 5.07 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.08:*:*:*:*:*:*:* | 5.08 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.09:*:*:*:*:*:*:* | 5.09 | Vulnerable | Stunnel |
- cpe:2.3:a:stunnel:stunnel:5.00:*:*:*:*:*:*:* Versions 5.00 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.01:*:*:*:*:*:*:* Versions 5.01 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.02:*:*:*:*:*:*:* Versions 5.02 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.03:*:*:*:*:*:*:* Versions 5.03 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.04:*:*:*:*:*:*:* Versions 5.04 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.05:*:*:*:*:*:*:* Versions 5.05 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.06:*:*:*:*:*:*:* Versions 5.06 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.07:*:*:*:*:*:*:* Versions 5.07 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.08:*:*:*:*:*:*:* Versions 5.08 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.09:*:*:*:*:*:*:* Versions 5.09 Vulnerable ·Stunnel
Show 4 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:stunnel:stunnel:5.10:*:*:*:*:*:*:* | 5.10 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.11:*:*:*:*:*:*:* | 5.11 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.12:*:*:*:*:*:*:* | 5.12 | Vulnerable | Stunnel |
| cpe:2.3:a:stunnel:stunnel:5.13:*:*:*:*:*:*:* | 5.13 | Vulnerable | Stunnel |
- cpe:2.3:a:stunnel:stunnel:5.10:*:*:*:*:*:*:* Versions 5.10 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.11:*:*:*:*:*:*:* Versions 5.11 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.12:*:*:*:*:*:*:* Versions 5.12 Vulnerable ·Stunnel
- cpe:2.3:a:stunnel:stunnel:5.13:*:*:*:*:*:*:* Versions 5.13 Vulnerable ·Stunnel
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
Not affected: 3 products
- Red Hat Enterprise Linux 5
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2015-3644
- 2026-10-03 Alias added: GHSA-3w38-w685-6793
References
Advisory 1
More Stunnel vulnerabilities
- TI-2011-02592 stunnel 4.40 and 4.41 might allow remote attackers to execute arbitrary code or cause a… CVSS 2.0HIGH 9.3
- TI-2001-00060 Format string vulnerability in stunnel 3.8 and earlier allows attackers to execute… CVSS 2.0HIGH 10.0
- TI-2002-00002 Format string vulnerability in stunnel before 3.22 when used in client mode for (1) smtp… CVSS 2.0HIGH 7.5
- TI-2021-03525 Improper certificate validation in stunnel CVSS 3.1HIGH 7.5
- TI-2013-01549 stunnel 4.21 through 4.54, when CONNECT protocol negotiation and NTLM authentication are… CVSS 2.0MEDIUM 6.6
- TI-2008-02320 The OCSP functionality in stunnel before 4.24 does not properly search certificate… CVSS 2.0MEDIUM 6.8
Sources
- CVE-2015-3644 · CVE Program
- CVE-2015-3644 · NVD
- FIRST EPSS
- GHSA-3w38-w685-6793 · GitHub Advisory Database · CC BY 4.0
- CVE-2015-3644 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences