# CVE-2026-90115: xsk: fix NULL pointer dereference in __xsk_rcv()

> A NULL pointer dereference in the Linux kernel's XSK receive path allows remote attackers to cause a system crash via crafted network packets.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102068, BELL-CVE-2026-90115, DEBIAN-CVE-2026-90115, GHSA-fwqw-j57j-h6cj, UBUNTU-CVE-2026-90115

## What is CVE-2026-90115?

CVE-2026-90115 is a vulnerability in Linux, published on 17 Sep 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:

xsk: fix NULL pointer dereference in __xsk_rcv()

In the __xsk_rcv() multi-buffer path, xsk_buff_alloc() is called in a
loop without checking its return value. xsk_buff_can_alloc() only
counts fill queue entries without validating their addresses, so it
can succeed while xsk_buff_alloc() rejects all remaining entries and
returns NULL.

  Oops: general protection fault, probably for non-canonical address
   0xdffffc0000000000
  KASAN: null-ptr-deref in range
   [0x0000000000000000-0x0000000000000007]
  RIP: 0010:__xsk_rcv+0x426/0xc20 (net/xdp/xsk.c:350)
  Call Trace:
   xsk_generic_rcv+0x26d/0x5f0
   xdp_do_generic_redirect+0x3c5/0xcf0
   do_xdp_generic+0x92f/0xe70
   __netif_receive_skb_core.constprop.0+0xf7e/0x2b30

Fix this with a two-stage transaction. First allocate and stage all
buffers required for the packet, recycling all staged buffers with
xsk_buff_free() if any allocation fails. Only after this stage
succeeds, copy the data, reserve the RX descriptors, and release the
buffers in an error-free loop.

## Which versions are affected by CVE-2026-90115?


## How do I fix CVE-2026-90115?

Apply the vendor's patch.

## Is CVE-2026-90115 being exploited?

There is no known exploitation of CVE-2026-90115 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90115 and fix it if it is affected.

What it is: CVE-2026-90115 is a vulnerability in Linux, published on 17 Sep 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-2026-90115 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-2026-90115/ (Markdown: https://insights.sbomify.com/CVE-2026-90115/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90115
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90115
- OSV: https://osv.dev/vulnerability/CVE-2026-90115

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90115/
Summaries are generated and may contain mistakes; the official description above is the record.