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CVE-2015-3644

17
FAUCET Score

CVE-2015-3644 describes a vulnerability in Stunnel versions 5.00 through 5.13 where the "redirect" option fails to properly redirect client connections to the intended server after the initial connection, enabling remote attackers to bypass authentication. With a CVSS score of 5.8, this medium-severity vulnerability has a network attack vector and medium attack complexity, potentially leading to partial confidentiality and integrity compromise. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
5.00CPE matchmatch criteria
cpe:2.3:a:stunnel:stunnel:5.00:*:*:*:*:*:*:*
5.01CPE matchmatch criteria
cpe:2.3:a:stunnel:stunnel:5.01:*:*:*:*:*:*:*
5.02CPE matchmatch criteria
cpe:2.3:a:stunnel:stunnel:5.02:*:*:*:*:*:*:*
5.03CPE matchmatch criteria
cpe:2.3:a:stunnel:stunnel:5.03:*:*:*:*:*:*:*
5.04CPE matchmatch criteria
cpe:2.3:a:stunnel:stunnel:5.04:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

5.8MEDIUM

AV:N/AC:M/Au:N/C:P/I:P/A:N

Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Exploitability Score
8.6
Impact Score
4.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
2.14%
Probability of exploitation in next 30 days
EPSS Percentile
80.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0214 is in the 67th percentile among its peer group of 19,955 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2015-3644Important

stunnel: authentication bypass with the "redirect" option

May 14, 2015

References

stunnel.org / CVE-2015-3644.html
PatchVendor Advisory
debian.org / security/2015/dsa-3299
securityfocus.com / bid/74659
securitytracker.com / id/1032324