CVEvulnerability
CVE-2021-20230
7.5 HIGH
Official page ↗
- Status
- Modified
- Published
- 2021-02-23
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CVSS 2.0 ([email protected])
- 5.0 MEDIUM — AV:N/AC:L/Au:N/C:P/I:N/A:N
- Weaknesses
- CWE-295
Description
A flaw was found in stunnel before 5.57, where it improperly validates client certificates when it is configured to use both redirect and verifyChain options. This flaw allows an attacker with a certificate signed by a Certificate Authority, which is not the one accepted by the stunnel server, to access the tunneled service instead of being redirected to the address specified in the redirect option. The highest threat from this vulnerability is to confidentiality.
Affected configurations
• stunnel stunnel (< 5.57)
Related
Weakness · CWE (1)
- CWE-295 Improper Certificate Validation weakness
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1925226 Issue Tracking, Third Party Advisory
- https://github.com/mtrojnar/stunnel/commit/ebad9ddc4efb2635f37174c9d800d06206f1edf9 Patch, Third Party Advisory
- https://security.gentoo.org/glsa/202105-02 Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1925226 Issue Tracking, Third Party Advisory
- https://github.com/mtrojnar/stunnel/commit/ebad9ddc4efb2635f37174c9d800d06206f1edf9 Patch, Third Party Advisory
- https://security.gentoo.org/glsa/202105-02 Third Party Advisory