CVE-2026-90140
Received
Received - Intake
BaseFortify
Vulnerability report for CVE-2026-90140, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-17
Last updated on: 2026-09-17
Assigner: kernel.org
Description
Description
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.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Linux | Linux | bfbab62ca69f72bcd14ea30de1fb98f6080ad464 |
| Linux | Linux | a8f650b93e55764ca9ff8e1ddebc151f57024086 |
| Linux | Linux | 535e9bd0e8f8d8cfdc29de7cdb902b5041427fe6 |
| Linux | Linux | 053fc4f755ad43cf35210677bcba798ccdc48d0c |
| Linux | Linux | 053fc4f755ad43cf35210677bcba798ccdc48d0c |
| Linux | Linux | 053fc4f755ad43cf35210677bcba798ccdc48d0c |
| Linux | Linux | 053fc4f755ad43cf35210677bcba798ccdc48d0c |
| Linux | Linux | 5.15.166 |
| Linux | Linux | 6.1.107 |
| Linux | Linux | 6.6.48 |
| Linux | Linux | 6.8 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
