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Review reviewHigh

CVE-2026-23270

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: net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks As Paolo said earlier [1]: "Since the blamed commit below, classify can return TC_ACT_CONSUMED while the current skb being held by the defragmentation engine. As reported by GangMin Kim, if such packet is that may cause a UaF when the defrag engine later on tries to tuch again such packet." act_ct was never meant to be used in the egress path, however some users are attaching it to egress today [2]. Attempting to reach a middle ground, we notice...

CVSS
7.8
EPSS
0.13%
2.60% percentile
CISA KEV
Not listed
Published
2026.03.19
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.13%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks As Paolo said earlier [1]: "Since the blamed commit below, classify can return TC_ACT_CONSUMED while the current skb being held by the defragmentation engine. As reported by GangMin Kim, if such packet is that may cause a UaF when the defrag engine later on tries to tuch again such packet." act_ct was never meant to be used in the egress path, however some users are attaching it to egress today [2]. Attempting to reach a middle ground, we notice...

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
>= 172ba7d46c202e679f3ccb10264c67416aaeb1c4 < bc4e5bb529823a09f02dbe96169de679a9db26e0, >= 0b5b831122fc3789fff75be433ba3e4dd7b779d4 < fb3c380a54e33d1fd272cc342faa906d787d7ef1, >= 73f7da5fd124f2cda9161e2e46114915e6e82e97 < 5a110ddcc99bda77a28598b3555fe009eaab3828, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < 524ce8b4ea8f64900b6c52b6a28df74f6bc0801e, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < 380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < 9deda0fcda5c1f388c5e279541850b71a2ccfcf4, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < 11cb63b0d1a0685e0831ae3c77223e002ef18189, >= f5346df0591d10bc948761ca854b1fae6d2ef441, >= 5.15.148 < 5.15.203, >= 6.1.75 < 6.1.167, >= 6.6.14 < 6.6.130, >= 6.7.2 < 6.8, >= 6.8, >= V3.1.6, >= V3.1.5, >= 6.8 < 6.12.77, >= 6.13 < 6.18.18, >= 6.19 < 6.19.8, 7.0
Fixed versions
5.15.203, 6.1.167, 6.6.130, 6.8, 6.12.77, 6.18.18, 6.19.8

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
CVE-2026-23270 — Linux Linux, SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | SECUFOCUS NOW