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Review reviewHigh

CVE-2025-21999

Linux Linux, SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP

In the Linux kernel, the following vulnerability has been resolved: proc: fix UAF in proc_get_inode() Fix race between rmmod and /proc/XXX's inode instantiation. The bug is that pde->proc_ops don't belong to /proc, it belongs to a module, therefore dereferencing it after /proc entry has been registered is a bug unless use_pde/unuse_pde() pair has been used. use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops never changes so information necessary for inode instantiation can be saved _before_ proc_register() in PDE itself and used later, avoiding pde->proc_ops->... derefer...

CVSS
7.8
EPSS
0.21%
10.8% percentile
CISA KEV
Not listed
Published
2025.04.03
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.21%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: proc: fix UAF in proc_get_inode() Fix race between rmmod and /proc/XXX's inode instantiation. The bug is that pde->proc_ops don't belong to /proc, it belongs to a module, therefore dereferencing it after /proc entry has been registered is a bug unless use_pde/unuse_pde() pair has been used. use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops never changes so information necessary for inode instantiation can be saved _before_ proc_register() in PDE itself and used later, avoiding pde->proc_ops->... derefer...

Affected product and versions

Product
Linux Linux, SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
Affected versions
>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < eda279586e571b05dff44d48e05f8977ad05855d, >= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa, >= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 966f331403dc3ed04ff64eaf3930cf1267965e53, >= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 63b53198aff2e4e6c5866a4ff73c7891f958ffa4, >= 97a32539b9568bb653683349e5a76d02ff3c3e2c < ede3e8ac90ae106f0b29cd759aadebc1568f1308, >= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 64dc7c68e040251d9ec6e989acb69f8f6ae4a10b, >= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 654b33ada4ab5e926cd9c570196fefa7bec7c1df, >= 5.6, >= V3.1.6, >= 2.6.23 < 6.1.132, >= 6.2 < 6.6.85, >= 6.7 < 6.12.21, >= 6.13 < 6.13.9, 6.14
Fixed versions
6.1.132, 6.6.85, 6.12.21, 6.13.9

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP 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