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Review reviewHigh

CVE-2021-47402

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: net: sched: flower: protect fl_walk() with rcu Patch that refactored fl_walk() to use idr_for_each_entry_continue_ul() also removed rcu protection of individual filters which causes following use-after-free when filter is deleted concurrently. Fix fl_walk() to obtain rcu read lock while iterating and taking the filter reference and temporary release the lock while calling arg->fn() callback that can sleep. KASAN trace: [ 352.773640] ================================================================== [ 352.775041] BUG: KASAN:...

CVSS
7.8
EPSS
0.24%
15.6% percentile
CISA KEV
Not listed
Published
2024.05.22
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.24%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: net: sched: flower: protect fl_walk() with rcu Patch that refactored fl_walk() to use idr_for_each_entry_continue_ul() also removed rcu protection of individual filters which causes following use-after-free when filter is deleted concurrently. Fix fl_walk() to obtain rcu read lock while iterating and taking the filter reference and temporary release the lock while calling arg->fn() callback that can sleep. KASAN trace: [ 352.773640] ================================================================== [ 352.775041] BUG: KASAN:...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= d39d714969cda5cbda291402c8c6b1fb1047f42e < 694b0cee7f8546b69a80996a29cb3cf4149c0453, >= d39d714969cda5cbda291402c8c6b1fb1047f42e < d0d520c19e7ea19ed38dc5797b12397b6ccf9f88, >= d39d714969cda5cbda291402c8c6b1fb1047f42e < dab4677bdbffa5c8270e79e34e51c89efa0728a0, >= d39d714969cda5cbda291402c8c6b1fb1047f42e < d5ef190693a7d76c5c192d108e8dec48307b46ee, >= 5.3, >= 5.3 < 5.4.151, >= 5.5 < 5.10.71, >= 5.11 < 5.14.10, 5.15
Fixed versions
5.4.151, 5.10.71, 5.14.10

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416
CVE-2021-47402 — Linux Linux, linux kernel | SECUFOCUS NOW