Skip to content
Noroxi
CVE-2026-64262· NVD / CVE Program· CNA Linux

fuse-uring: end fuse_req on io-uring cancel task work

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: 0.15% (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 4f45f276d5b4412eade6f74f2e37f3adba0473ed, bb476ef8e1027a9d509fbaaf81f5061a07e9e5a7, bea4fe98204b6ce7eb8e29f7bf867dd7619b3ddd.

Low priority for now. Upgrade to Linux Linux 4f45f276d5b4412eade6f74f2e37f3adba0473ed, bb476ef8e1027a9d509fbaaf81f5061a07e9e5a7, bea4fe98204b6ce7eb8e29f7bf867dd7619b3ddd 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: fuse-uring: end fuse_req on io-uring cancel task work When io_uring delivers task work with tw.cancel set (PF_EXITING, PF_KTHREAD fallback, or percpu_ref_is_dying on the ring context), fuse_uring_send_in_task() takes the cancel branch, assigns -ECANCELED, and falls through to fuse_uring_send(). That path only flips the entry to FRRS_USERSPACE and completes the io_uring cmd; it never discharges the ring entry's owning reference to the fuse_req that fuse_uring_add_req_to_ring_ent() handed it at dispatch time. fuse_uring_send_in_task() tw.cancel == true err = -ECANCELED fuse_uring_send(ent, cmd, err, issue_flags) ent->state = FRRS_USERSPACE list_move(&ent->list, &queue->ent_in_userspace) ent->cmd = NULL io_uring_cmd_done(-ECANCELED) /* ent->fuse_req still set, req still hashed */ The fuse_req stays linked on fpq->processing[hash] and fuse_request_end() is never invoked. The originating syscall thread blocks in D-state in request_wait_answer() until fuse_abort_conn() runs, which can be the entire connection lifetime. For FR_BACKGROUND requests fc->num_background is never decremented either, so repeated cancels inflate the counter until max_background is hit and all later background ops stall. tw.cancel does not imply a connection abort (e.g. a single io_uring worker thread exits while the fuse connection stays up), so this cannot be left for fuse_abort_conn() to clean up. Ending the req but still routing the entry through fuse_uring_send() is not enough: that leaves a req-less entry on ent_in_userspace, and ent_list_request_expired() dereferences ent->fuse_req unconditionally on the head of that list, which would then NULL-deref. Fix the cancel branch to release the entry directly. Remove it from the queue, complete the io_uring cmd, end the fuse_req, free the entry, and drop its queue_refs (waking the teardown waiter if it was the last).

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jul 25, 2026
Updated
Aug 17, 2026
EPSS
0.1% · 4th 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%

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-64262

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

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 kernel6.14 and later · before 6.18.39
  • linux linux kernel6.19 and later · before 7.1.4

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

    • 6.14affected
    • c2c9af9a0b13261c36909036057a116f2edb5e1a and later · before bb476ef8e1027a9d509fbaaf81f5061a07e9e5a7affected · git
    • c2c9af9a0b13261c36909036057a116f2edb5e1a and later · before 4f45f276d5b4412eade6f74f2e37f3adba0473edaffected · git
    • c2c9af9a0b13261c36909036057a116f2edb5e1a and later · before bea4fe98204b6ce7eb8e29f7bf867dd7619b3dddaffected · git
    • before 6.14not affected · semver
    • 6.18.39 and later · up to and including 6.18.*not affected · semver
    • 7.1.4 and later · up to and including 7.1.*not affected · semver
    • 7.2 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:14linuxbefore 7.1.4-17.1.4-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • 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
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-64260Jul 25, 2026 · fuse-uring: Avoid queue->stopped races and set/read that value under lock
    31Monitor
  • ← EarlierCVE-2026-64261Jul 25, 2026 · fuse-uring: Avoid use-after-free in fuse_uring_async_stop_queues
    31Monitor
  • Later →CVE-2026-64263Jul 25, 2026 · fuse-uring: fix moving cancelled entry to ent_in_userspace list
    22Monitor

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 Linux4f45f276d5b4412eade6f74f2e37f3adba0473edVendor (CNA)
Linux Linuxbb476ef8e1027a9d509fbaaf81f5061a07e9e5a7Vendor (CNA)
Linux Linuxbea4fe98204b6ce7eb8e29f7bf867dd7619b3dddVendor (CNA)
debian:linux7.1.4-1 · Debian:14Package 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.

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).

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. Fix✗ → ✓

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

References

Show all references (2 more)

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

All records