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NVD / CVE Program· CNA Linux

CVE-2026-52990: fsnotify: fix inode reference leak in fsnotify_recalc_mask()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 4aca914ac152f5d055ddcb36704d1e539ac08977, 5.11, 5.16.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 4aca914ac152f5d055ddcb36704d1e539ac08977, 5.11, 5.16 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: fix inode reference leak in fsnotify_recalc_mask() fsnotify_recalc_mask() fails to handle the return value of __fsnotify_recalc_mask(), which may return an inode pointer that needs to be released via fsnotify_drop_object() when the connector's HAS_IREF flag transitions from set to cleared. This manifests as a hung task with the following call trace: INFO: task umount:1234 blocked for more than 120 seconds. Call Trace: __schedule schedule fsnotify_sb_delete generic_shutdown_super kill_anon_super cleanup_mnt task_work_run do_exit do_group_exit The race window that triggers the iref leak: Thread A (adding mark) Thread B (removing mark) ────────────────────── ──────────────────────── fsnotify_add_mark_locked(): fsnotify_add_mark_list(): spin_lock(conn->lock) add mark_B(evictable) to list spin_unlock(conn->lock) return /* ---- gap: no lock held ---- */ fsnotify_detach_mark(mark_A): spin_lock(mark_A->lock) clear ATTACHED flag on mark_A spin_unlock(mark_A->lock) fsnotify_put_mark(mark_A) fsnotify_recalc_mask(): spin_lock(conn->lock) __fsnotify_recalc_mask(): /* mark_A skipped: ATTACHED cleared */ /* only mark_B(evictable) remains */ want_iref = false has_iref = true /* not yet cleared */ -> HAS_IREF transitions true -> false -> returns inode pointer spin_unlock(conn->lock) /* BUG: return value discarded! * iput() and fsnotify_put_sb_watched_objects() * are never called */ Fix this by deferring the transition true -> false of HAS_IREF flag from fsnotify_recalc_mask() (Thread A) to fsnotify_put_mark() (thread B).

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 24, 2026
Updated
Nov 6, 2026
EPSS
0.1% · 2th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.10.220 and later · before 5.11
  • linux linux kernel5.15.154 and later · before 5.16
  • linux linux kernel5.19 and later · before 6.12.91
  • linux linux kernel6.13 and later · before 6.18.33
  • linux linux kernel6.19 and later · before 7.0.10
  • linux linux kernel7.1

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

    • ff34ebaa6f6dc1eebce6a8d6f12a1566f33d00fe, 4f145b67c075324b13d6ae7d5abb6e7a1dbac26d, 5.19affected
    • c3638b5b13740fa31762d414bbce8b7a694e582a and later · before ba4d88bfd58739698a9bd2309659c9cc26acf7f7affected · git
    • c3638b5b13740fa31762d414bbce8b7a694e582a and later · before 926ec3937b28d30c08427053c8d8af7f9e086d82affected · git
    • c3638b5b13740fa31762d414bbce8b7a694e582a and later · before 8c8afa6444e6bdc145d2bf2f3aeeca6da3e36b42affected · git
    • c3638b5b13740fa31762d414bbce8b7a694e582a and later · before b740cc86816bbc87902ae9db74cd21abde3c8d63affected · git
    • c3638b5b13740fa31762d414bbce8b7a694e582a and later · before 5c80289503da3658e3df80280598c68d181eadbdaffected · git
    • c3638b5b13740fa31762d414bbce8b7a694e582a and later · before 4aca914ac152f5d055ddcb36704d1e539ac08977affected · git
    • 5.10.220 and later · before 5.11affected · semver
    • 5.15.154 and later · before 5.16affected · semver
    • before 5.19not 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 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.10-17.0.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-52986Jun 24, 2026 · netfilter: nf_conntrack_sip: don't use simple_strtoul
    39Monitor
  • ← EarlierCVE-2026-52988Jun 24, 2026 · netfilter: nf_tables: join hook list via splice_list_rcu() in commit phase
    28Monitor
  • Later →CVE-2026-52991Jun 24, 2026 · sched/psi: fix race between file release and pressure write
    31Monitor

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 Linux4aca914ac152f5d055ddcb36704d1e539ac08977Vendor (CNA)
Linux Linux5.11Vendor (CNA)
Linux Linux5.16Vendor (CNA)
Linux Linux5c80289503da3658e3df80280598c68d181eadbdVendor (CNA)
Linux Linux8c8afa6444e6bdc145d2bf2f3aeeca6da3e36b42Vendor (CNA)
Linux Linux926ec3937b28d30c08427053c8d8af7f9e086d82Vendor (CNA)
Linux Linuxb740cc86816bbc87902ae9db74cd21abde3c8d63Vendor (CNA)
Linux Linuxba4d88bfd58739698a9bd2309659c9cc26acf7f7Vendor (CNA)
debian:linux6.12.94-1 · 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.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

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

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (5 more)

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

All records