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High 7.8Published Feb 4, 2026

CVE-2026-23083fou: Don't allow 0 for FOU_ATTR_IPPROTO.

Updated under an hour ago ()

Does this affect you?

It affects Linux and 4 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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 HIGH (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
Not given
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Linux
NVD analysis
Modified
Record last updated
Oct 15, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Linux Linux
linux:linux (from the name)
from 23461551c00628c3f3fe9cf837bf53cf8f212b63 before c7498f9bc390479ccfad7c7f2332237ff4945b03; 23461551c00628c3f3fe9cf837bf53cf8f212b63 builds before 611ef4bd9c73d9e6d87bed57a635ff1fdd8c91ea; 23461551c00628c3f3fe9cf837bf53cf8f212b63 builds before 6e983789b7588ee59cbf303583546c043bad8e19; 23461551c00628c3f3fe9cf837bf53cf8f212b63 builds before 1cc98b8887cabb1808d2f4a37cd10a7be7574771; from 23461551c00628c3f3fe9cf837bf53cf8f212b63 before b7db31a52c3862a1a32202a273a4c32e7f5f4823; 23461551c00628c3f3fe9cf837bf53cf8f212b63 builds before 9b75dff8446ec871030d8daf5a69e74f5fe8b956; 23461551c00628c3f3fe9cf837bf53cf8f212b63 builds before 7a9bc9e3f42391e4c187e099263cf7a1c4b69ff5
CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
linux linux_kernel
linux:linux_kernel
from 3.18 before 5.10.249; from 5.11 before 5.15.199; from 5.16 before 6.1.162; from 6.2 before 6.6.122; from 6.7 before 6.12.68; from 6.13 before 6.18.8; 6.19; 6.19; and 4 more ranges
NVD

References

  • patch
  • patch
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  • patch

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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