What’s Vulnerable › Vulnerabilities

CVE-2021-41990

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 7.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-18 · updated 2026-06-17
• Weakness: CWE-190

Description

The gmp plugin in strongSwan before 5.9.4 has a remote integer overflow via a crafted certificate with an RSASSA-PSS signature. For example, this can be triggered by an unrelated self-signed CA certificate sent by an initiator. Remote code execution cannot occur.

Affected products

• Debian Linux: 10.0, 11.0
• Fedoraproject Fedora: 33, 34, 35
• Siemens 6Gk5615-0Aa00-2Aa2 Firmware: all versions
• Siemens 6Gk5804-0Ap00-2Aa2 Firmware: all versions
• Siemens 6Gk5812-1Aa00-2Aa2 Firmware: all versions
• Siemens 6Gk5812-1Ba00-2Aa2 Firmware: all versions
• Siemens 6Gk5816-1Aa00-2Aa2 Firmware: all versions
• Siemens 6Gk5816-1Ba00-2Aa2 Firmware: all versions
• Siemens 6Gk5826-2Ab00-2Ab2 Firmware: all versions
• Siemens 6Gk5856-2Ea00-3Aa1 Firmware: all versions
• Siemens 6Gk5856-2Ea00-3Da1 Firmware: all versions
• Siemens 6Gk5874-2Aa00-2Aa2 Firmware: all versions
• Siemens 6Gk5874-3Aa00-2Aa2 Firmware: all versions
• Siemens 6Gk5876-3Aa02-2Ba2 Firmware: all versions
• Siemens 6Gk5876-3Aa02-2Ea2 Firmware: all versions
• Siemens 6Gk5876-4Aa00-2Ba2 Firmware: all versions
• Siemens 6Gk5876-4Aa00-2Da2 Firmware: all versions
• Siemens 6Gk6108-4Am00-2Ba2 Firmware: all versions
• Siemens 6Gk6108-4Am00-2Da2 Firmware: all versions
• strongSwan: from 5.6.1 before 5.9.4 — fixed in 5.9.4

How to fix

Upgrade to a fixed version: strongSwan 5.9.4. Check the vendor advisory for mitigations.

References

• https://cert-portal.siemens.com/productcert/pdf/ssa-539476.pdf
• https://github.com/strongswan/strongswan/releases/tag/5.9.4
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5FJSATD2R2XHTG4P63GCMQ2N7EWKMME5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WQSQ3BEC22NF4NCDZVCT4P3Q2ZIAJXGJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y3TQ32JLJOBJDB2EJKSX2PBPB5NFG2D4/
• https://www.debian.org/security/2021/dsa-4989
• https://www.strongswan.org/blog/2021/10/18/strongswan-vulnerability-%28cve-2021-41990%29.html
• https://cert-portal.siemens.com/productcert/pdf/ssa-539476.pdf
• https://github.com/strongswan/strongswan/releases/tag/5.9.4
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5FJSATD2R2XHTG4P63GCMQ2N7EWKMME5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WQSQ3BEC22NF4NCDZVCT4P3Q2ZIAJXGJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y3TQ32JLJOBJDB2EJKSX2PBPB5NFG2D4/

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