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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-99175: fsnotify: prevent mark additions during connector teardown

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 36ebddca56b9d8993d6dc984fdecc748ee1f5e06, 472589eacdf10b5f9bd10b333957ed5291b2544b, 587d80966dcce2824f13fd32dab83bf882acf66f.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 36ebddca56b9d8993d6dc984fdecc748ee1f5e06, 472589eacdf10b5f9bd10b333957ed5291b2544b, 587d80966dcce2824f13fd32dab83bf882acf66f or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Oct 28, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.12affected
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before f7def717c06aea7004905e4d1568c3691ef9825daffected · git
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before da2f9aa89ef1b1fe7a7c6e1a8ddacd9c975e86aaaffected · git
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before 587d80966dcce2824f13fd32dab83bf882acf66faffected · git
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before d28a460a2237220d9ccbdd3baac6eaead44e96cbaffected · git
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before 61133f15773b907bada651a02d9c6d38eae37c48affected · git
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before 952501bfc6e5e654ac4a17ec9d90c1ec614bd9f1affected · git
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before 472589eacdf10b5f9bd10b333957ed5291b2544baffected · git
    • 6b3f05d24d355f50f3d9814304650fcab0efb482 and later · before 36ebddca56b9d8993d6dc984fdecc748ee1f5e06affected · git
    • before 4.12not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-26.12.115-2

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-99173Oct 28, 2026 · eventfs: Free the eventfs_inode after an rcu grace period too
    31Monitor
  • ← EarlierCVE-2026-99174Oct 28, 2026 · ext4: free the sbi after a grace period
    0Monitor
  • Later →CVE-2026-99176Oct 28, 2026 · KVM: nVMX: Reset MMU back to the root MMU if loading L2 state fails for !VM-Entry
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux36ebddca56b9d8993d6dc984fdecc748ee1f5e06Vendor (CNA)
Linux Linux472589eacdf10b5f9bd10b333957ed5291b2544bVendor (CNA)
Linux Linux587d80966dcce2824f13fd32dab83bf882acf66fVendor (CNA)
Linux Linux61133f15773b907bada651a02d9c6d38eae37c48Vendor (CNA)
Linux Linux952501bfc6e5e654ac4a17ec9d90c1ec614bd9f1Vendor (CNA)
Linux Linuxd28a460a2237220d9ccbdd3baac6eaead44e96cbVendor (CNA)
Linux Linuxda2f9aa89ef1b1fe7a7c6e1a8ddacd9c975e86aaVendor (CNA)
Linux Linuxf7def717c06aea7004905e4d1568c3691ef9825dVendor (CNA)
debian:linux6.12.115-2 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 5, 2026+8 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records