CVE-2026-74550: net: do not send ICMP/NDISC Redirects when peer allocation fails
In the Linux kernel, the following vulnerability has been resolved:
net: do not send ICMP/NDISC Redirects when peer allocation fails
When inetgetpeerv4() or inetgetpeerv6() 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, iprtsendredirect() called icmpsend() directly when peer == NULL. In IPv6, ip6forward() and ndiscsendredirect() passed a NULL peer into inetpeerxrlimallow(), which returned true when peer == NULL.
Because ICMP/NDISC Redirects are not part of the default global rate limit mask (sysctlicmpratemask), sending redirects when peer == NULL creates an un-rate-limited ICMP packet storm.
Fix this by failing closed in iprtsendredirect(), ip6forward(), and ndiscsendredirect() when peer is NULL.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Linux kernel net: do not send ICMP/NDISC Redirects when peer allocation fails under memory pressure or tree size capsto a version that resolves this vulnerability.Patch net: do not send ICMP/NDISC Redirects when peer allocation fails
Event History
Frequently Asked Questions
What is the severity of CVE-2026-74550?
CVE-2026-74550 has a risk score of 32, indicating a low to moderate severity level.
How do I fix CVE-2026-74550?
To resolve CVE-2026-74550, update your Linux kernel to the latest version, as the vulnerability has been patched.
What impact does CVE-2026-74550 have on systems?
CVE-2026-74550 can lead to issues with ICMP and NDISC redirects under specific memory pressure scenarios, potentially affecting network performance.
Which versions of the Linux kernel are affected by CVE-2026-74550?
CVE-2026-74550 affects specific versions of the Linux kernel that have not yet applied the associated patch.
Is there a workaround for CVE-2026-74550?
Though the best solution is to update the kernel, there is no widely recommended workaround for CVE-2026-74550.