Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-08-22T00:00:00 kernel: ipvs: clear IPv4 options after rebasing tunnel ICMP errors 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-787

In the Linux kernel, the following vulnerability has been resolved: ipvs: clear IPv4 options after rebasing tunnel ICMP errors ip_vs_in_icmp() rebases an skb from the outer ICMP packet to the quoted original request before passing it to icmp_send(). However, IPCB(skb)->opt still describes the outer IPv4 header. A timestamp option in the outer header can therefore leave an offset that points into the quoted transport header after the rebase. __ip_options_echo() treats a byte at that stale location as the option length and copies it into the fixed-size option storage on the __icmp_send() stack, causing a stack out-of-bounds write. Clear the stale option metadata after resetting the network header. Keep the remaining control block fields, including the ingress interface used by the ICMP response path.

A flaw was found in the Linux kernel's IP Virtual Server (IPVS) component. When processing Internet Control Message Protocol (ICMP) errors for tunneled packets, the system can incorrectly use a stale IPv4 option offset. A remote attacker could exploit this by sending a specially crafted ICMP packet, leading to a stack out-of-bounds write. This vulnerability could result in a denial of service or potentially arbitrary code execution.

To mitigate this issue, prevent the `ip_vs` kernel module from loading. This can be achieved by creating a blacklist rule. 1. Unload the module if currently loaded: `sudo modprobe -r ip_vs` 2. Create a blacklist configuration file: `echo "blacklist ip_vs" | sudo tee /etc/modprobe.d/disable-ip_vs.conf` 3. Rebuild the initial RAM disk to ensure the module is not loaded at boot: `sudo dracut -f` A system reboot is required for the changes to take full effect. Disabling this module will prevent the use of IP Virtual Server (IPVS) functionality. Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Affected kernel Red Hat Enterprise Linux 7 Affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-74669 https://nvd.nist.gov/vuln/detail/CVE-2026-74669 https://lore.kernel.org/linux-cve-announce/2026082229-CVE-2026-74669-f574@gregkh/T