CVE-2026-46040 — inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < 3ab58cf42c46bf2366d2f55ae5c59299d5e178b7≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < 10edf7e0ffdc7faa18e2244b17722c1b882b8273≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < 3ad9ccea1b25435f6179b57aa891960beb7ce8f9≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < 8bcc1cd237ab5ccfdd102869fa031c541943cf40≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < 73ddc8518a32baff6bc17afda4ee1ebae5b4ed12≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < fdaa42ca370d056428e5e171247c8fdce8dff36a≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < 9e48844f708eb48bae4e79cb21edc097c966306d≥ 1cce1eea0aff51201753fcaca421df825b0813b6 and < 6a320935fa4293e9e599ec9f85dc9eb3be7029f8 and 1 moreversion 4.11 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel | ≥ 4.11 and < 5.10.258≥ 5.11 and < 5.15.209≥ 5.16 and < 6.1.175≥ 6.2 and < 6.6.140≥ 6.7 and < 6.12.86≥ 6.13 and < 6.18.27≥ 6.19 and < 7.0.4 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.5 | CVSS 3.1 | Medium | 1.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
| 5.5 | CVSS 3.1 | Medium | — | — | GitHub, Inc. via GitHub Security Advisories |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.17%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 5.5
- Source status changed · → Modified
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
13 on the record
- git.kernel.org/stable/c/73ddc8518a32baff6bc17afda4ee1ebae5b4ed12
- git.kernel.org/stable/c/8bcc1cd237ab5ccfdd102869fa031c541943cf40
- git.kernel.org/stable/c/6a320935fa4293e9e599ec9f85dc9eb3be7029f8
- git.kernel.org/stable/c/3ab58cf42c46bf2366d2f55ae5c59299d5e178b7
- git.kernel.org/stable/c/9e48844f708eb48bae4e79cb21edc097c966306d
- git.kernel.org/stable/c/10edf7e0ffdc7faa18e2244b17722c1b882b8273
- git.kernel.org/stable/c/3ad9ccea1b25435f6179b57aa891960beb7ce8f9
- git.kernel.org/stable/c/fdaa42ca370d056428e5e171247c8fdce8dff36a
- nvd.nist.gov/vuln/detail/CVE-2026-46040
- cert-portal.siemens.com/productcert/html/ssa-457936.html
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-784472.html
- github.com/advisories/GHSA-38g3-xqxq-2v2p
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 12h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 12h
- Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
- Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 1d
- Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 1d
- Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-46040 is "inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 0.17% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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