Medium severity · published May 27, 2026
CVE-2026-46040
inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails
5.5
CVSS
0.1%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails
When fsnotify_add_inode_mark_locked() fails in inotify_new_watch(),
the error path calls inotify_remove_from_idr() but does not call
dec_inotify_watches() to undo the preceding inc_inotify_watches().
This leaks a watch count, and repeated failures can exhaust the
max_user_watches limit with -ENOSPC even when no watches are active.
Prior to commit 1cce1eea0aff ("inotify: Convert to using per-namespace
limits"), the watch count was incremented after fsnotify_add_mark_locked()
succeeded, so this path was not affected. The conversion moved
inc_inotify_watches() before the mark insertion without adding the
corresponding rollback.
Add the missing dec_inotify_watches() call in the error path.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 2% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
4.11 before 5.10.258; 5.11 before 5.15.209; 5.16 before 6.1.175; 6.2 before 6.6.140; 6.7 before 6.12.86; 6.13 before 6.18.27; +1 more · source: NVD
LI
Linux · Linux
1cce1eea0aff51201753fcaca421df825b0813b6 before 3ab58cf42c46bf2366d2f55ae5c59299d5e178b7; 1cce1eea0aff51201753fcaca421df825b0813b6 before 10edf7e0ffdc7faa18e2244b17722c1b882b8273; 1cce1eea0aff51201753fcaca421df825b0813b6 before 3ad9ccea1b25435f6179b57aa891960beb7ce8f9; 1cce1eea0aff51201753fcaca421df825b0813b6 before 8bcc1cd237ab5ccfdd102869fa031c541943cf40; 1cce1eea0aff51201753fcaca421df825b0813b6 before 73ddc8518a32baff6bc17afda4ee1ebae5b4ed12; 1cce1eea0aff51201753fcaca421df825b0813b6 before fdaa42ca370d056428e5e171247c8fdce8dff36a; +3 more · source: vendor
SS
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7; V3.1.6; V3.1.7 · source: CISA
SS
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7; V3.1.6; V3.1.7 · source: CISA
SS
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem · Siemens
0 · source: CISA
SS
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-46040
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-46040
Patch
https://git.kernel.org/stable/c/10edf7e0ffdc7faa18e2244b17722c1b882b8273
Patch
https://git.kernel.org/stable/c/3ab58cf42c46bf2366d2f55ae5c59299d5e178b7
Patch
https://git.kernel.org/stable/c/3ad9ccea1b25435f6179b57aa891960beb7ce8f9
Patch
https://git.kernel.org/stable/c/6a320935fa4293e9e599ec9f85dc9eb3be7029f8
Patch
https://git.kernel.org/stable/c/73ddc8518a32baff6bc17afda4ee1ebae5b4ed12
Patch
https://git.kernel.org/stable/c/8bcc1cd237ab5ccfdd102869fa031c541943cf40
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