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CVE-2026-90140

Vulnerability in Linux kernel (CVE-2026-90140)

Summary

Vulnerability in Linux kernel (CVE-2026-90140). Risk of unauthorized operations or information disclosure.

Original description

The description as published by the source.

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                            |
                                     |
                  |
                                     |  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 th…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-90140 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-90140" on the vendor's site.

CVE-2026-90140 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。

  2. 2
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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