CVE-2018-6918

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 4.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-04-04 · updated 2026-06-17
Weakness: CWE-835

Description

In FreeBSD before 11.1-STABLE, 11.1-RELEASE-p9, 10.4-STABLE, 10.4-RELEASE-p8 and 10.3-RELEASE-p28, the length field of the ipsec option header does not count the size of the option header itself, causing an infinite loop when the length is zero. This issue can allow a remote attacker who is able to send an arbitrary packet to cause the machine to crash.

Affected products

FreeBSD: from 10.0 before 10.4; from 11.0 before 11.1 — fixed in 10.4, 11.1

How to fix

Upgrade to a fixed version: FreeBSD 10.4, 11.1. Check the vendor advisory for mitigations.

References

http://seclists.org/fulldisclosure/2019/Jun/6
http://www.securityfocus.com/bid/103666
http://www.securitytracker.com/id/1040628
https://seclists.org/bugtraq/2019/May/77
https://security.FreeBSD.org/advisories/FreeBSD-SA-18:05.ipsec.asc
https://support.apple.com/kb/HT210090
https://support.apple.com/kb/HT210091
http://seclists.org/fulldisclosure/2019/Jun/6
http://www.securityfocus.com/bid/103666
http://www.securitytracker.com/id/1040628
https://seclists.org/bugtraq/2019/May/77
https://security.FreeBSD.org/advisories/FreeBSD-SA-18:05.ipsec.asc

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