CVE-2026-31579

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. ]

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/1c52ef00e391144334f10995985c2f256d4be982	Patch
https://git.kernel.org/stable/c/60a25ef8dacb3566b1a8c4de00572a498e2a3bf9	Patch
https://git.kernel.org/stable/c/9a9e69155b2091b8297afaf1533b8d68a3096841	Patch
https://git.kernel.org/stable/c/a1d0f6cbb962af29586e3e65a4bced1a5e39221f	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::

History

No history.

Information

Published : 2026-04-24 15:16

Updated : 2026-06-17 10:34

NVD link : CVE-2026-31579

Mitre link : CVE-2026-31579

CVE.ORG link : CVE-2026-31579

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-476

NULL Pointer Dereference

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This causes a hung task when another\nthread holds rtnl_mutex - the cleanup_net workqueue (or the\nsetup_net failure rollback path) blocks indefinitely in\nwg_netns_pre_exit() waiting to acquire the lock.\n\nConvert to .exit_rtnl, introduced in commit 7a60d91c690b (\"net:\nAdd ->exit_rtnl() hook to struct pernet_operations.\"), where the\nframework already holds RTNL and batches all callbacks under a\nsingle rtnl_lock()/rtnl_unlock() pair, eliminating the contention\nwindow.\n\nThe rcu_assign_pointer(wg->creating_net, NULL) is safe to move\nfrom .pre_exit to .exit_rtnl (which runs after synchronize_rcu())\nbecause all RCU readers of creating_net either use maybe_get_net()\n- which returns NULL for a dying namespace with zero refcount - or\naccess net->user_ns which remains valid throughout the entire\nops_undo_list sequence.\n\n[ Jason: added __net_exit and __read_mostly annotations that were missing. ]"}], "lastModified": "2026-06-17T10:34:01.017", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E7BFA239-2F39-4B24-92AA-6F60AA187C18", "versionEndExcluding": "6.18.24"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D6A8A074-BBF4-4803-ABED-519A839435BB", "versionEndExcluding": "6.19.14", "versionStartIncluding": "6.19"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "9B5888AB-7403-4335-89E4-21CC0B48366A", "versionEndExcluding": "7.0.1", "versionStartIncluding": "7.0"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}