What is CVE-2021-47507?

CVE-2021-47507 is a medium-severity vulnerability in Linux, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 4.7/10. Published 2024-05-24.

How severe is CVE-2021-47507?

Medium severity. CVSS v3 base score is 4.7 out of 10.

Vulnerability in Linux

CVE-2021-47507

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

Vulnerability class: Race Condition

EPSS: 0.002 (8.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Linux — versions 7c7cb07d4affcf41749234fe9dc4d90cd3959e32, 5.4.102, 5.10.85
Linux Linux_kernel — versions 5.16

Weakness classification (CWE)

CWE-362 — Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)

Frequently asked questions

What is CVE-2021-47507?: CVE-2021-47507 is a medium-severity vulnerability in Linux, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 4.7/10. Published 2024-05-24.
How severe is CVE-2021-47507?: Medium severity. CVSS v3 base score is 4.7 out of 10.