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CVE-2021-3450

7.4 · HIGH

The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain.

Published Mar 25, 2021CWE-295EPSS 18.34%

Overview

CVE-2021-3450 is a high-severity vulnerability. It was published on March 25, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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 verifica

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refwww.openwall.com/lists/oss-security/2021/03/27/1Refwww.openwall.com/lists/oss-security/2021/03/27/2Refwww.openwall.com/lists/oss-security/2021/03/28/3Refwww.openwall.com/lists/oss-security/2021/03/28/4Refcert-portal.siemens.com/productcert/pdf/ssa-389290.pdfRefgit.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=2a40b7bc7b94dd7de897a74571e7024f0cf0d63bRefkb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845Refkc.mcafee.com/corporate/index?page=content&id=SB10356Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/Refmta.openssl.org/pipermail/openssl-announce/2021-March/000198.html

How CyberStrike helps

Frequently asked questions

What is CVE-2021-3450?

CVE-2021-3450 is a high-severity vulnerability. It was published on March 25, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).

How severe is CVE-2021-3450?

This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-3450?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-3450?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-3450 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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