CVE-2021-47507 - CVE House
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Status published Medium CVE-2021-47507

nfsd: Fix nsfd startup race (again)

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: Fix nsfd startup race (again) Commit bd5ae9288d64 ("nfsd: register pernet ops last, unregister first") has re-opened rpc_pipefs_event() race against nfsd_net_id registration (register_pernet_subsys()) which has been fixed by commit bb7ffbf29e76 ("nfsd: fix nsfd startup race triggering BUG_ON"). Restore the order of register_pernet_subsys() vs register_cld_notifier(). Add WARN_ON() to prevent a future regression. Crash info: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000012 CPU: 8 PID: 345 Comm: mount Not tainted 5.4.144-... #1 pc : rpc_pipefs_event+0x54/0x120 [nfsd] lr : rpc_pipefs_event+0x48/0x120 [nfsd] Call trace: rpc_pipefs_event+0x54/0x120 [nfsd] blocking_notifier_call_chain rpc_fill_super get_tree_keyed rpc_fs_get_tree vfs_get_tree do_mount ksys_mount __arm64_sys_mount el0_svc_handler el0_svc

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

Linux
Vulnerable Versions:
8677e99150b0830d29cc1318b4cc559e176940bb, 7c7cb07d4affcf41749234fe9dc4d90cd3959e32, bd5ae9288d6451bd346a1b4a59d4fe7e62ba29b7, 4d41f65efeec0a6da6088341203c81e49ebfcd90, 5.4.102, 5.10.20, 5.11.3, 5.12, 0, 5.4.165, 5.10.85, 5.15.8, 5.16

Timeline

Official Publish: May 24th, 2024
Last Modified: May 23rd, 2026
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)

No CWE data available

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.