CVE-2026-74550

Summary

In the Linux kernel, the following vulnerability has been resolved:

net: do not send ICMP/NDISC Redirects when peer allocation fails

When inet_getpeer_v4() or inet_getpeer_v6() fails to allocate a peer entry under memory pressure or tree size caps, redirect handlers previously fell back to sending un-rate-limited ICMP/NDISC Redirect messages.

In IPv4, ip_rt_send_redirect() called icmp_send() directly when peer == NULL. In IPv6, ip6_forward() and ndisc_send_redirect() passed a NULL peer into inet_peer_xrlim_allow(), which returned true when peer == NULL.

Because ICMP/NDISC Redirects are not part of the default global rate limit mask (sysctl_icmp_ratemask), sending redirects when peer == NULL creates an un-rate-limited ICMP packet storm.

Fix this by failing closed in ip_rt_send_redirect(), ip6_forward(), and ndisc_send_redirect() when peer is NULL.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux92d8682926342d2b6aa5b2ecc02221e00e1573a0 < f5ecaa7ea7686fa7ecdb6affc9d3a9a42e4524b1affected
LinuxLinux92d8682926342d2b6aa5b2ecc02221e00e1573a0 < 21666f7af49a90ef44d474916b8ef4402dfd74f5affected
LinuxLinux92d8682926342d2b6aa5b2ecc02221e00e1573a0 < 5ec5f00fc606a6df8434948c4552b3cb1176595daffected
LinuxLinux92d8682926342d2b6aa5b2ecc02221e00e1573a0 < 828f6670d110ff2bf44c743037b38badc315704caffected
LinuxLinux92d8682926342d2b6aa5b2ecc02221e00e1573a0 < dbc3791e3b2472e1ccc08947e0f83b443470ff4faffected
LinuxLinux2.6.39affected
LinuxLinux0 < 2.6.39unaffected
LinuxLinux6.6.151 <= 6.6.*unaffected
LinuxLinux6.12.103 <= 6.12.*unaffected
LinuxLinux6.18.44 <= 6.18.*unaffected
LinuxLinux7.1.8 <= 7.1.*unaffected
LinuxLinux7.2-rc6 <= *unaffected

Weaknesses

References