CVE-2026-98073
Received Received - Intake

Memory Leak in Linux Kernel Network Namespace

Publication date: 2026-09-25

Last updated on: 2026-09-25

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: net: Remove conflicting altnames for dying netns in __dev_change_net_namespace(). syzbot reported the warning in cfg80211_pernet_exit(). [0] The repro does the following: 1. create two device in root netns and non-root netns 2. assign the same altname for the two devices 3. remove the non-root netns Since commit 7663d522099e ("net: check for altname conflicts when changing netdev's netns"), cfg80211_switch_netns() and cfg802154_switch_netns() fail if init_net has a device with the conflicting altname. default_device_exit_net() had the same issue and commit d09486a04f5d ("net: fix removing a namespace with conflicting altnames") fixed it. cfg80211_pernet_exit() and cfg802154_pernet_exit() need the same fix. Let's generalise the fix by removing conflicting altnames for dying netns in __dev_change_net_namespace(). [0]: cfg80211_switch_netns(rdev, &init_net) WARNING: net/wireless/core.c:1871 at cfg80211_pernet_exit+0xd5/0x120 net/wireless/core.c:1871, CPU#1: kworker/u8:9/1160 Modules linked in: CPU: 1 UID: 0 PID: 1160 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: netns cleanup_net RIP: 0010:cfg80211_pernet_exit+0xd5/0x120 net/wireless/core.c:1871 Code: e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 b4 ef 0e f7 4d 8b 36 49 81 fe 20 10 4a 90 74 12 e8 03 3d 9f f6 eb 85 e8 fc 3c 9f f6 90 <0f> 0b 90 eb cc e8 f1 3c 9f f6 eb 05 e8 ea 3c 9f f6 5b 41 5c 41 5e RSP: 0018:ffffc900057a78f0 EFLAGS: 00010293 RAX: ffffffff8b287154 RBX: ffff88807ba72780 RCX: ffff8880213e8000 RDX: 0000000000000000 RSI: 00000000ffffffef RDI: 0000000000000000 RBP: 00000000ffffffef R08: ffffffff9024cc67 R09: 0000000000000000 R10: fffff52000af4eb0 R11: fffffbfff204998d R12: dffffc0000000000 R13: ffffffff904a1080 R14: ffff888144ed0008 R15: ffff888144ed0e20 FS: 0000000000000000(0000) GS:ffff888124de6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005642de0a8a70 CR3: 000000007a40c000 CR4: 00000000003526f0 Call Trace: <TASK> ops_exit_list net/core/net_namespace.c:200 [inline] ops_undo_list+0x43d/0x8d0 net/core/net_namespace.c:253 cleanup_net+0x572/0x810 net/core/net_namespace.c:706 process_one_work kernel/workqueue.c:3387 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK>

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Meta Information

Published
2026-09-25
Last Modified
2026-09-25
Generated
2026-09-25
AI Q&A
2026-09-25
EPSS Evaluated
N/A
NVD
CVE-2026-98073
EUVD
EUVD-2026-86726

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a conflict in network device alternate names (altnames) when changing a network device's namespace. The issue occurs when two devices in different network namespaces share the same altname, and one namespace is removed. The kernel fails to handle this conflict properly, leading to a warning in cfg80211_pernet_exit().

Detection Guidance

This vulnerability is related to Linux kernel network namespace handling and conflicting altname assignments. Detection requires checking kernel logs for warnings during network namespace cleanup and verifying altname conflicts in network devices. Monitor logs for cfg80211_pernet_exit warnings or similar messages during netns operations.

Impact Analysis

This vulnerability could cause system instability or crashes during network namespace cleanup operations. It may lead to kernel warnings or errors when removing network namespaces with conflicting device altnames, potentially disrupting network services.

Mitigation Strategies

Apply the kernel patch that resolves this issue by removing conflicting altnames during netns cleanup. Update to a kernel version containing the fix (commit d09486a04f5d or later). Monitor for related warnings in system logs and ensure network device configurations do not have duplicate altnames.

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