f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances
CVSS score
5.5
EPSS probability
%0.2
Risk score
0.0
Published
2 y ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2021-47335 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances As syzbot reported, there is an use-after-free issue during f2fs recovery: Use-after-free write at 0xffff88823bc16040 (in kfence-#10): kmem_cache_destroy+0x1f/0x120 mm/slab_common.c:486 f2fs_recover_fsync_data+0x75b0/0x8380 fs/f2fs/recovery.c:869 f2fs_fill_super+0x9393/0xa420 fs/f2fs/super.c:3945 mount_bdev+0x26c/0x3a0 fs/super.c:1367 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x86/0x270 fs/super.c:1497 do_new_mount fs/namespace.c:2905 [inline] path_mount+0x196f/0x2be0 fs/namespace.c:3235 do_mount fs/namespace.c:3248 [inline] __do_sys_mount fs/namespace.c:3456 [inline] __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae The root cause is multi f2fs filesystem instances can race on accessing global fsync_entry_slab pointer, result in use-after-free issue of slab cache, fixes to init/destroy this slab cache only once during module init/destroy procedure to avoid this issue.
IMPACT: Affected Products and Software
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 5.5 | CVSS V31 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-47335 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-47335 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
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