CVE-2021-47507

MediumCVSS 4.7/10Last modified Jun 17, 2026

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

Metrics

CVSS 3.1 4.7/10CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

CWE-362

Affected software

VendorProductVersions
LinuxLinux>= 8677e99150b0830d29cc1318b4cc559e176940bb, < f5734b1714ca355703e9ea8fb61d04beff1790b9; >= 7c7cb07d4affcf41749234fe9dc4d90cd3959e32, < c520943a00ad5015704969ad3304c956bcd49d25; >= bd5ae9288d6451bd346a1b4a59d4fe7e62ba29b7, < 8bf902fee5893cfc2f04a698abab47629699ae9a; >= bd5ae9288d6451bd346a1b4a59d4fe7e62ba29b7, < b10252c7ae9c9d7c90552f88b544a44ee773af64; 4d41f65efeec0a6da6088341203c81e49ebfcd90; >= 5.4.102, < 5.4.165; >= 5.10.20, < 5.10.85; >= 5.11.3, < 5.12
LinuxLinux5.12

References

Timeline

Published
May 24, 2024
Last modified
Jun 17, 2026
NVD status
Analyzed

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CVE-2021-47507: Medium severity, CVSS 4.7 | Vulnix