CVE-2026-99175UnratedRevised 7 Nov

fsnotify: prevent mark additions during connector teardown

MSRC advisory NVD CVE.org

Assessment

Severity: Unrated
CVSS base score: Not published
Impact: Not stated
Exploitation detected: Unknown: not stated by MSRC
Exploitability: Not assessed
Publicly disclosed: Unknown: not stated by MSRC
EPSS · 30-day forecast: No EPSS score collected
Customer action: Required: follow the MSRC remediation guidance

More details

Public detection template: No Nuclei template is listed in the current collected catalog
Component: Mariner
Weakness: —
Issued by: Linux
Published: 29 Oct 2026 · October 2026
Last revised: 7 Nov 2026Information published.

Updates that fix it

0 KBs

No KB listed

No KB update is listed in the collected MSRC record. Check the MSRC advisory for product releases and other remedies.

Affected products

Open Source Software

1 affected product

azl3 kernel 6.6.159.1-1 on Azure Linux 3.0

What changed

Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
6 Nov 2026 · 17:32:22 UTC
Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
6 Nov 2026 · 16:31:02 UTC

Page history

Changes are dated when recorded; day views use the last saved version from that UTC day, and citations stay fixed.

Cite this version

Field-level log (9)

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7 Nov 2026 · 08:59:22 UTC Last revised5 Nov 2026 14:46 UTC → 7 Nov 2026 01:49 UTC
6 Nov 2026 · 17:32:22 UTC Public detection templateUnknown: detection-template evidence is incomplete or retained → No Nuclei template listed
6 Nov 2026 · 17:32:22 UTC Source coverage: public-exploit-codeIncomplete → Current
6 Nov 2026 · 17:32:22 UTC Source coverage: first-epssIncomplete → Current
6 Nov 2026 · 17:32:22 UTC Source coverage: msrc-cvrfIncomplete → Current
6 Nov 2026 · 16:31:02 UTC Public detection templateNo Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
6 Nov 2026 · 16:31:02 UTC Source coverage: public-exploit-codeCurrent → Incomplete
6 Nov 2026 · 16:31:02 UTC Source coverage: first-epssCurrent → Incomplete
6 Nov 2026 · 16:31:02 UTC Source coverage: msrc-cvrfCurrent → Incomplete

Explore global source statements, affected packages and advisory history for CVE-2026-99175. The catalog has a separate collection scope from Microsoft release records.

Collected exploitation and prediction evidence

Risk source coverage

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-99175

Published

fsnotify: prevent mark additions during connector teardown

In the Linux kernel, the following vulnerability has been resolved: fsnotify: prevent mark additions during connector teardown fsnotify_destroy_marks() keeps a reference to its current mark while it drops conn->lock to destroy the mark. This stabilizes the forward-walk cursor, but does not prevent a new mark from being inserted before it. For example, an inotify watch re-added after IN_IGNORED sorts before the old, detached mark for the same group. The walk can miss the replacement and then detach the entire connector from the object. The replacement is still on its group's marks_list and, for inotify, in the watch IDR. The group mutex no longer protects the connector's object from disappearing. An unprivileged fdinfo read racing the final detach can consequently call igrab(NULL): BUG: KASAN: null-ptr-deref in igrab+0x24/0x100 Write of size 4 at addr 0000000000000148 Call Trace: igrab+0x24/0x100 inotify_show_fdinfo+0x1dc/0x5e0 seq_show+0x397/0x690 Set a DESTROYING flag under conn->lock before starting the walk, and reject new marks on that connector with -ENOENT. The existing add-mark error paths undo the temporary group-list entry and the backend's watch allocation. Do not wait for teardown while holding the group mutex, which the destroyer needs. Once the old connector is detached, an add can install a fresh connector as before. This closes the insertion race for all object types using the common connector teardown, without changing the mark reference or SRCU lifetime rules.

Source published: 28 Oct 2026 10:35:29 UTC
Source modified: 30 Oct 2026 12:42:39 UTC
Observed here: 30 Oct 2026 13:45:33 UTC
Source terms: CVE Program Terms of Use

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