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CVE-2023-4809

7.5 · HIGH

In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed.

Published Sep 6, 2023CWE-167EPSS 0.80%

Overview

CVE-2023-4809 is a high-severity vulnerability. It was published on September 6, 2023 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

In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed. That is, a packet with multiple fragment extension headers would not be recognized as the correct ultimate payload. Instead a packet with multiple IPv6 fragment headers would unexpectedly be interpreted as a fragmented packet, rather than as whatever the real payload is.

As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host.

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/2023/09/08/5Refwww.openwall.com/lists/oss-security/2023/09/08/6Refwww.openwall.com/lists/oss-security/2023/09/08/7Refsecurity.FreeBSD.org/advisories/FreeBSD-SA-23:10.pf.ascRefsecurity.netapp.com/advisory/ntap-20231221-0009/Refwww.openwall.com/lists/oss-security/2023/09/08/5Refwww.openwall.com/lists/oss-security/2023/09/08/6Refwww.openwall.com/lists/oss-security/2023/09/08/7Refsecurity.FreeBSD.org/advisories/FreeBSD-SA-23:10.pf.ascRefsecurity.netapp.com/advisory/ntap-20231221-0009/

How CyberStrike helps

Frequently asked questions

What is CVE-2023-4809?

CVE-2023-4809 is a high-severity vulnerability. It was published on September 6, 2023 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2023-4809?

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-2023-4809?

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-2023-4809?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2023-4809 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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