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Review reviewHigh

CVE-2026-23083

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: fou: Don't allow 0 for FOU_ATTR_IPPROTO. fou_udp_recv() has the same problem mentioned in the previous patch. If FOU_ATTR_IPPROTO is set to 0, skb is not freed by fou_udp_recv() nor "resubmit"-ted in ip_protocol_deliver_rcu(). Let's forbid 0 for FOU_ATTR_IPPROTO.

CVSS
7.8
EPSS
0.13%
2.96% percentile
CISA KEV
Not listed
Published
2026.02.05
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: fou: Don't allow 0 for FOU_ATTR_IPPROTO. fou_udp_recv() has the same problem mentioned in the previous patch. If FOU_ATTR_IPPROTO is set to 0, skb is not freed by fou_udp_recv() nor "resubmit"-ted in ip_protocol_deliver_rcu(). Let's forbid 0 for FOU_ATTR_IPPROTO.

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
>= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < c7498f9bc390479ccfad7c7f2332237ff4945b03, >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < 611ef4bd9c73d9e6d87bed57a635ff1fdd8c91ea, >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < 6e983789b7588ee59cbf303583546c043bad8e19, >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < 1cc98b8887cabb1808d2f4a37cd10a7be7574771, >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < b7db31a52c3862a1a32202a273a4c32e7f5f4823, >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < 9b75dff8446ec871030d8daf5a69e74f5fe8b956, >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < 7a9bc9e3f42391e4c187e099263cf7a1c4b69ff5, >= 3.18, >= V3.1.6, >= 3.18 < 5.10.249, >= 5.11 < 5.15.199, >= 5.16 < 6.1.162, >= 6.2 < 6.6.122, >= 6.7 < 6.12.68, >= 6.13 < 6.18.8, 6.19
Fixed versions
5.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.68, 6.18.8

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
Not available