What’s Vulnerable › Vulnerabilities

CVE-2018-8753

• Severity: medium (CVSS 5.9 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-08-15 · updated 2026-06-17

Description

The IKEv1 implementation in Clavister cOS Core before 11.00.11, 11.20.xx before 11.20.06, and 12.00.xx before 12.00.09 allows remote attackers to decrypt RSA-encrypted nonces by leveraging a Bleichenbacher attack.

Affected products

• Clavister Cos Core: before 11.00.11; from 11.20.00 before 11.20.06; from 12.00.00 before 12.00.09 — fixed in 11.00.11, 11.20.06, 12.00.09

How to fix

Upgrade to a fixed version: Clavister Cos Core 11.00.11, 11.20.06, 12.00.09. Check the vendor advisory for mitigations.

References

• https://web-in-security.blogspot.com/2018/08/practical-bleichenbacher-attacks-on-ipsec-ike.html
• https://www.clavister.com/advisories/security/clav-sa-0157-bleichenbacher-oracle-vulnerability-in-ikev1
• https://web-in-security.blogspot.com/2018/08/practical-bleichenbacher-attacks-on-ipsec-ike.html
• https://www.clavister.com/advisories/security/clav-sa-0157-bleichenbacher-oracle-vulnerability-in-ikev1

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