# CVE-2026-74473: vxlan: use pskb_network_may_pull() in route_shortcircuit()

> A missing network header pull in the Linux kernel VXLAN driver allows out-of-bounds reads, potentially causing crashes or information leaks.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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-96497, BELL-CVE-2026-74473, DEBIAN-CVE-2026-74473, GHSA-h9rh-wf2h-cr4c, UBUNTU-CVE-2026-74473

## What is CVE-2026-74473?

CVE-2026-74473 is a critical memory corruption 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:

vxlan: use pskb_network_may_pull() in route_shortcircuit()

route_shortcircuit() currently calls pskb_may_pull(skb, sizeof(struct iphdr))
(or ipv6hdr), which checks if bytes are available starting from skb->data.

However, in vxlan_xmit(), skb->data points to the MAC header, so
skb_network_offset(skb) is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, 20)
only checks 20 bytes from skb->data (which is 14 bytes MAC header + 6 bytes of
IP header), leaving the rest of the IP header potentially un-pulled in non-linear
frags. Subsequent dereferences of ip_hdr(skb)->daddr can read beyond the pulled
linear buffer length.

Fix this by using pskb_network_may_pull(), which adds skb_network_offset(skb) to
the length check to ensure the full network header is present in the linear buffer.

## Which versions are affected by CVE-2026-74473?


## How do I fix CVE-2026-74473?

Apply the vendor's patch.

## Is CVE-2026-74473 being exploited?

There is no known exploitation of CVE-2026-74473 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74473 and fix it if it is affected.

What it is: CVE-2026-74473 is a critical memory corruption 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-2026-74473 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-2026-74473/ (Markdown: https://insights.sbomify.com/CVE-2026-74473/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74473
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74473
- OSV: https://osv.dev/vulnerability/CVE-2026-74473

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74473/
Summaries are generated and may contain mistakes; the official description above is the record.