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NVD / CVE Program· CNA Linux

CVE-2026-90140: cuse: wait for pending RCU callbacks on module exit

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: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 389bd349ddbcf90dbd8a4f2a4ab6e552d53df134, 45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e, 4deb3edead0c0e172cc7349e8855d741d3c5e162; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 389bd349ddbcf90dbd8a4f2a4ab6e552d53df134, 45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e, 4deb3edead0c0e172cc7349e8855d741d3c5e162; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 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: cuse: wait for pending RCU callbacks on module exit Since commit 053fc4f755ad ("fuse: fix UAF in rcu pathwalks"), fuse_conn_put() frees the fuse_conn through call_rcu() rather than synchronously. For cuse, fc->release is cuse_fc_release(), which lives in the cuse module. If the module is removed before the RCU grace period ends, the callback jumps into freed module memory: userspace / module unload | RCU softirq ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ close(/dev/cuse) | cuse_channel_release() | fuse_dev_release() | fuse_conn_put(fch->conn) | call_rcu(delayed_release) ------+---> callback queued | rmmod cuse | cuse_exit() | cuse_channel_destroy() | ... | return | | <module text freed> | | rcu_do_batch() | delayed_release() | fc->release() | -> cuse_fc_release() | ^^^ freed text! The freed module text is unmapped by vfree(), so the jump into the stale callback triggers a page-fault Oops. If the virtual address is subsequently reused, the callback could execute unrelated code (undefined behaviour). Fix this by calling rcu_barrier() in cuse_exit() so that any pending fuse_conn release callback completes before the module is removed.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 11th 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 · 0.2%

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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

    • 6.8affected
    • bfbab62ca69f72bcd14ea30de1fb98f6080ad464 and later · before 7fe415e1cd8fa875be263670c0ab47109818abb6affected · git
    • a8f650b93e55764ca9ff8e1ddebc151f57024086 and later · before 45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0eaffected · git
    • 535e9bd0e8f8d8cfdc29de7cdb902b5041427fe6 and later · before ac5c499413385cea3e0220d6050408d50842891daffected · git
    • 053fc4f755ad43cf35210677bcba798ccdc48d0c and later · before a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9affected · git
    • 053fc4f755ad43cf35210677bcba798ccdc48d0c and later · before 389bd349ddbcf90dbd8a4f2a4ab6e552d53df134affected · git
    • 053fc4f755ad43cf35210677bcba798ccdc48d0c and later · before c40f3f24839f8404325a2099e26c2a04786ae309affected · git
    • 053fc4f755ad43cf35210677bcba798ccdc48d0c and later · before 4deb3edead0c0e172cc7349e8855d741d3c5e162affected · git
    • 5.15.166 and later · before 5.15.221affected · semver
    • 6.1.107 and later · before 6.1.188affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

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-2026-90138Sep 17, 2026 · vsock: don't check the listener's sk_err in vsock_accept()
    0Monitor
  • ← EarlierCVE-2026-90139Sep 17, 2026 · fuse: check for NULL root inode in fuse_fill_super_submount
    0Monitor
  • Later →CVE-2026-90141Sep 17, 2026 · ipvs: fix integer overflow in ftp helper port/address parsing
    29Monitor

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 Linux389bd349ddbcf90dbd8a4f2a4ab6e552d53df134Vendor (CNA)
Linux Linux45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0eVendor (CNA)
Linux Linux4deb3edead0c0e172cc7349e8855d741d3c5e162Vendor (CNA)
Linux Linux5.15.221Vendor (CNA)
Linux Linux6.1.188Vendor (CNA)
Linux Linux6.6.157Vendor (CNA)
Linux Linux7fe415e1cd8fa875be263670c0ab47109818abb6Vendor (CNA)
Linux Linuxa1b46aee33d83f14ed62d7fdef1a91d3e0b732a9Vendor (CNA)
Linux Linuxac5c499413385cea3e0220d6050408d50842891dVendor (CNA)
Linux Linuxc40f3f24839f8404325a2099e26c2a04786ae309Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package 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

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. Fix✗ → ✓

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References

Show all references (6 more)

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

All records