CVE-2023-42754: Kernel: ipv4: null pointer dereference in ipv4_send_dest_unreach()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-10-05 · updated 2026-10-15
Weakness: CWE-476

Description

A NULL pointer dereference flaw was found in the Linux kernel ipv4 stack. The socket buffer (skb) was assumed to be associated with a device before calling __ip_options_compile, which is not always the case if the skb is re-routed by ipvs. This issue may allow a local user with CAP_NET_ADMIN privileges to crash the system.

Affected products

Fedoraproject Fedora: 37, 38, 39
Linux kernel: before 6.6; 6.6-rc1, 6.6-rc2 — fixed in 6.6
Red Hat Enterprise Linux: 8.0, 9.0

How to fix

Upgrade to a fixed version: Linux kernel 6.6. Check the vendor advisory for mitigations.

References

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