# CVE-2026-31579: wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit

Status: published. Published: 2026-04-24. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit

wg_netns_pre_exit() manually acquires rtnl_lock() inside the
pernet .pre_exit callback.  This causes a hung task when another
thread holds rtnl_mutex - the cleanup_net workqueue (or the
setup_net failure rollback path) blocks indefinitely in
wg_netns_pre_exit() waiting to acquire the lock.

Convert to .exit_rtnl, introduced in commit 7a60d91c690b ("net:
Add ->exit_rtnl() hook to struct pernet_operations."), where the
framework already holds RTNL and batches all callbacks under a
single rtnl_lock()/rtnl_unlock() pair, eliminating the contention
window.

The rcu_assign_pointer(wg->creating_net, NULL) is safe to move
from .pre_exit to .exit_rtnl (which runs after synchronize_rcu())
because all RCU readers of creating_net either use maybe_get_net()
- which returns NULL for a dying namespace with zero refcount - or
access net->user_ns which remains valid throughout the entire
ops_undo_list sequence.

[ Jason: added __net_exit and __read_mostly annotations that were missing. ]

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 900575aa33a3eaaef802b31de187a85c4a4b4bd0; < 707607db2193591b68c0e70f814133472c185b1e (affected, git); ≥ 900575aa33a3eaaef802b31de187a85c4a4b4bd0; < 9a9e69155b2091b8297afaf1533b8d68a3096841 (affected, git); ≥ 900575aa33a3eaaef802b31de187a85c4a4b4bd0; < 1c52ef00e391144334f10995985c2f256d4be982 (affected, git); ≥ 900575aa33a3eaaef802b31de187a85c4a4b4bd0; < a1d0f6cbb962af29586e3e65a4bced1a5e39221f (affected, git); ≥ 900575aa33a3eaaef802b31de187a85c4a4b4bd0; < 60a25ef8dacb3566b1a8c4de00572a498e2a3bf9 (affected, git); 363cc6efdbb54bb06cd5034a69b41aae974a736f (affected, git); ≥ 5.7.7; < 5.8 (affected, semver). Source: CNA: Linux
- Linux / Linux: 5.8 (affected); ≥ 0; < 5.8 (unaffected, semver); ≥ 6.12.114; ≤ 6.12.* (unaffected, semver); ≥ 6.18.24; ≤ 6.18.* (unaffected, semver); ≥ 6.19.14; ≤ 6.19.* (unaffected, semver); ≥ 7.0.1; ≤ 7.0.* (unaffected, semver); ≥ 7.1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.15% as of 2026-11-05; percentile 4.65%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/707607db2193591b68c0e70f814133472c185b1e (CNA: Linux)

- https://git.kernel.org/stable/c/9a9e69155b2091b8297afaf1533b8d68a3096841 (CNA: Linux)

- https://git.kernel.org/stable/c/1c52ef00e391144334f10995985c2f256d4be982 (CNA: Linux)

- https://git.kernel.org/stable/c/a1d0f6cbb962af29586e3e65a4bced1a5e39221f (CNA: Linux)

- https://git.kernel.org/stable/c/60a25ef8dacb3566b1a8c4de00572a498e2a3bf9 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-31579; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-31579; retrieved 2026-11-05; source updated Not reported

Revision: 0be24405226efb0de9890be354e5b6353dfc33e348ae445c0a6ab12813a10f7c

Canonical: https://y2.dev/cve/CVE-2026-31579

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