Description

The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. OpenSSL versions 1.1.1h and newer are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j).

Metrics

CVSS 3.1 7.4/10CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Weakness enumeration

CWE-295

Affected software

Vendor	Product	Versions
OpenSSL	OpenSSL	Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j)

References

http://www.openwall.com/lists/oss-security/2021/03/27/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/27/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/28/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/28/4Mailing List, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdfThird Party Advisory
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=2a40b7bc7b94dd7de897a74571e7024f0cf0d63b
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845Third Party Advisory
https://kc.mcafee.com/corporate/index?page=content&id=SB10356Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/
https://mta.openssl.org/pipermail/openssl-announce/2021-March/000198.htmlMailing List, Vendor Advisory
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013Third Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.ascThird Party Advisory
https://security.gentoo.org/glsa/202103-03Third Party Advisory
https://security.netapp.com/advisory/ntap-20210326-0006/Third Party Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJdThird Party Advisory
https://www.openssl.org/news/secadv/20210325.txtVendor Advisory
https://www.oracle.com//security-alerts/cpujul2021.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuApr2021.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
https://www.tenable.com/security/tns-2021-05Third Party Advisory
https://www.tenable.com/security/tns-2021-08Third Party Advisory
https://www.tenable.com/security/tns-2021-09Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/27/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/27/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/28/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/28/4Mailing List, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdfThird Party Advisory
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=2a40b7bc7b94dd7de897a74571e7024f0cf0d63b
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845Third Party Advisory
https://kc.mcafee.com/corporate/index?page=content&id=SB10356Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/
https://mta.openssl.org/pipermail/openssl-announce/2021-March/000198.htmlMailing List, Vendor Advisory
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013Third Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.ascThird Party Advisory
https://security.gentoo.org/glsa/202103-03Third Party Advisory
https://security.netapp.com/advisory/ntap-20210326-0006/Third Party Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJdThird Party Advisory
https://www.openssl.org/news/secadv/20210325.txtVendor Advisory
https://www.oracle.com//security-alerts/cpujul2021.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuApr2021.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
https://www.tenable.com/security/tns-2021-05Third Party Advisory
https://www.tenable.com/security/tns-2021-08Third Party Advisory
https://www.tenable.com/security/tns-2021-09Third Party Advisory

Timeline

Published: Mar 25, 2021
Last modified: Oct 8, 2026
NVD status: Modified

CVE-2021-3450