What’s Vulnerable › Vulnerabilities

CVE-2021-3773

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-02-16 · updated 2026-06-17
• Weakness: CWE-200

Description

A flaw in netfilter could allow a network-connected attacker to infer openvpn connection endpoint information for further use in traditional network attacks.

Affected products

• Fedoraproject Fedora: 34
• Linux kernel: before 5.14; from 5.15 before 5.15.15 — fixed in 5.14, 5.15.15
• Oracle Communications Cloud Native Core Binding Support Function: 22.1.3
• Oracle Communications Cloud Native Core Network Exposure Function: 22.1.1
• Oracle Communications Cloud Native Core Policy: 22.2.0
• Red Hat Enterprise Linux: 6.0, 7.0, 8.0

How to fix

Upgrade to a fixed version: Linux kernel 5.14, 5.15.15. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=2004949
• https://citizenlab.ca/2024/07/vulnerabilities-in-vpns-paper-presented-at-the-privacy-enhancing-technologies-symposium-2024/
• https://www.oracle.com/security-alerts/cpujul2022.html
• https://bugzilla.redhat.com/show_bug.cgi?id=2004949
• https://citizenlab.ca/2024/07/vulnerabilities-in-vpns-paper-presented-at-the-privacy-enhancing-technologies-symposium-2024/
• https://security.netapp.com/advisory/ntap-20250328-0004/
• https://www.oracle.com/security-alerts/cpujul2022.html

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