CVE-2015-2923

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-02-20 · updated 2026-06-17
Weakness: CWE-20

Description

The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in FreeBSD through 10.1 allows remote attackers to reconfigure a hop-limit setting via a small hop_limit value in a Router Advertisement (RA) message.

Affected products

FreeBSD: before 10.1 — fixed in 10.1

How to fix

Upgrade to a fixed version: FreeBSD 10.1. Check the vendor advisory for mitigations.

References

http://openwall.com/lists/oss-security/2015/04/04/2
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6fd99094de2b83d1d4c8457f2c83483b2828e75a
https://lists.freebsd.org/pipermail/freebsd-net/2015-April/041934.html
https://www.freebsd.org/security/advisories/FreeBSD-SA-15:09.ipv6.asc
http://openwall.com/lists/oss-security/2015/04/04/2
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6fd99094de2b83d1d4c8457f2c83483b2828e75a
https://lists.freebsd.org/pipermail/freebsd-net/2015-April/041934.html
https://www.freebsd.org/security/advisories/FreeBSD-SA-15:09.ipv6.asc

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