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CVE-2021-41991

7.5 · HIGH

The in-memory certificate cache in strongSwan before 5.9.4 has a remote integer overflow upon receiving many requests with different certificates to fill the cache and later trigger the replacement…

Published Oct 18, 2021CWE-190EPSS 5.30%

Overview

CVE-2021-41991 is a high-severity vulnerability. It was published on October 18, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

The in-memory certificate cache in strongSwan before 5.9.4 has a remote integer overflow upon receiving many requests with different certificates to fill the cache and later trigger the replacement of cache entries. The code attempts to select a less-often-used cache entry by means of a random number generator, but this is not done correctly. Remote code execution might be a slight possibility.

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

Refcert-portal.siemens.com/productcert/pdf/ssa-539476.pdfGitHubgithub.com/strongswan/strongswan/releases/tag/5.9.4Reflists.debian.org/debian-lts-announce/2021/10/msg00014.htmlReflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5FJSATD2R2XHTG4P63GCMQ2N7EWKMME5/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WQSQ3BEC22NF4NCDZVCT4P3Q2ZIAJXGJ/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y3TQ32JLJOBJDB2EJKSX2PBPB5NFG2D4/Refwww.debian.org/security/2021/dsa-4989Refwww.strongswan.org/blog/2021/10/18/strongswan-vulnerability-%28cve-2021-41991%29.htmlRefcert-portal.siemens.com/productcert/pdf/ssa-539476.pdfGitHubgithub.com/strongswan/strongswan/releases/tag/5.9.4

How CyberStrike helps

Frequently asked questions

What is CVE-2021-41991?

CVE-2021-41991 is a high-severity vulnerability. It was published on October 18, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2021-41991?

This vulnerability has a CVSS 3.1 base score of 7.5, 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-2021-41991?

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-2021-41991?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-41991 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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