CVE-2023-3107

Remote denial of service in IPv6 fragment reassembly

Description

A set of carefully crafted ipv6 packets can trigger an integer overflow in the calculation of a fragment reassembled packet's payload length field. This allows an attacker to trigger a kernel panic, resulting in a denial of service.

Remediation

Workaround:

  • Users with IPv6 disabled on untrusted network interfaces are not affected. Such interfaces will have the IFDISABLED nd6 flag set in ifconfig(8). The kernel may be configured to drop all IPv6 fragments by setting the net.inet6.ip6.maxfrags sysctl to 0. Doing so will prevent the bug from being triggered, with the caveat that legitimate IPv6 fragments will be dropped. If the pf(4) firewall is enabled, and scrubbing and fragment reassembly is enabled on untrusted interfaces, the bug cannot be triggered. This is the default if pf(4) is enabled.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
EPSS 0.12%
Vendor Advisory FreeBSD.org
Affected: FreeBSD FreeBSD
Published at:
Updated at:

References

Link Tags
https://security.FreeBSD.org/advisories/FreeBSD-SA-23:06.ipv6.asc mitigation vendor advisory
https://security.netapp.com/advisory/ntap-20230804-0001/ third party advisory

Frequently Asked Questions

What is the severity of CVE-2023-3107?
CVE-2023-3107 has been scored as a high severity vulnerability.
How to fix CVE-2023-3107?
As a workaround for remediating CVE-2023-3107: Users with IPv6 disabled on untrusted network interfaces are not affected. Such interfaces will have the IFDISABLED nd6 flag set in ifconfig(8). The kernel may be configured to drop all IPv6 fragments by setting the net.inet6.ip6.maxfrags sysctl to 0. Doing so will prevent the bug from being triggered, with the caveat that legitimate IPv6 fragments will be dropped. If the pf(4) firewall is enabled, and scrubbing and fragment reassembly is enabled on untrusted interfaces, the bug cannot be triggered. This is the default if pf(4) is enabled.
Is CVE-2023-3107 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2023-3107 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2023-3107?
CVE-2023-3107 affects FreeBSD FreeBSD.
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