CVE-2021-46972

Advisory lineage Upstream: 0 Downstream: 4
Analyzed
Published: 27 Feb 2024, 18:47
Last modified:11 May 2026, 13:45

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
<0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

27 Feb 2024, 18:47
Published
Vulnerability first disclosed
11 May 2026, 13:45
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: ovl: fix leaked dentry Since commit 6815f479ca90 ("ovl: use only uppermetacopy state in ovl_lookup()"), overlayfs doesn't put temporary dentry when there is a metacopy error, which leads to dentry leaks when shutting down the related superblock: overlayfs: refusing to follow metacopy origin for (/file0) ... BUG: Dentry (____ptrval____){i=3f33,n=file3} still in use (1) [unmount of overlay overlay] ... WARNING: CPU: 1 PID: 432 at umount_check.cold+0x107/0x14d CPU: 1 PID: 432 Comm: unmount-overlay Not tainted 5.12.0-rc5 #1 ... RIP: 0010:umount_check.cold+0x107/0x14d ... Call Trace: d_walk+0x28c/0x950 ? dentry_lru_isolate+0x2b0/0x2b0 ? __kasan_slab_free+0x12/0x20 do_one_tree+0x33/0x60 shrink_dcache_for_umount+0x78/0x1d0 generic_shutdown_super+0x70/0x440 kill_anon_super+0x3e/0x70 deactivate_locked_super+0xc4/0x160 deactivate_super+0xfa/0x140 cleanup_mnt+0x22e/0x370 __cleanup_mnt+0x1a/0x30 task_work_run+0x139/0x210 do_exit+0xb0c/0x2820 ? __kasan_check_read+0x1d/0x30 ? find_held_lock+0x35/0x160 ? lock_release+0x1b6/0x660 ? mm_update_next_owner+0xa20/0xa20 ? reacquire_held_locks+0x3f0/0x3f0 ? __sanitizer_cov_trace_const_cmp4+0x22/0x30 do_group_exit+0x135/0x380 __do_sys_exit_group.isra.0+0x20/0x20 __x64_sys_exit_group+0x3c/0x50 do_syscall_64+0x45/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae ... VFS: Busy inodes after unmount of overlay. Self-destruct in 5 seconds. Have a nice day... This fix has been tested with a syzkaller reproducer.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 1%

Techniques & Countermeasures

  • CWE-401•Missing Release of Memory after Effective Lifetime

    The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Systems

  • linux•linux

    ≥ 6815f479ca90ee7fd2e28b2a420f796b974155fe, < 71d58457a8afc650da5d3292a7f7029317654d95 | ≥ 6815f479ca90ee7fd2e28b2a420f796b974155fe, < cf3e3330bc5719fa9d658e3e2f596bde89344a94 | ≥ 6815f479ca90ee7fd2e28b2a420f796b974155fe, < d587cfaef72b1b6f4b2774827123bce91f497cc8 | ≥ 6815f479ca90ee7fd2e28b2a420f796b974155fe, < eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 | 5.8

  • linux•linux_kernel

    ≥ 5.8, < 5.10.35 | ≥ 5.11, < 5.11.19 | ≥ 5.12, < 5.12.2

References (4)