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

> Attackers can trigger un-rate-limited ICMP/NDISC Redirect storms when peer allocation fails, causing denial of service in the Linux kernel.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-96495, BELL-CVE-2026-74550, DEBIAN-CVE-2026-74550, GHSA-9cch-cjjm-3m2c, UBUNTU-CVE-2026-74550

## What is CVE-2026-74550?

CVE-2026-74550 is a high-severity denial of service vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2026-74550?


## How do I fix CVE-2026-74550?

Apply the vendor's patch.

## Is CVE-2026-74550 being exploited?

There is no known exploitation of CVE-2026-74550 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74550 and fix it if it is affected.

What it is: CVE-2026-74550 is a high-severity denial of service vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74550 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74550/ (Markdown: https://insights.sbomify.com/CVE-2026-74550/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74550
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74550
- OSV: https://osv.dev/vulnerability/CVE-2026-74550

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74550/
Summaries are generated and may contain mistakes; the official description above is the record.