High 7.8Published Feb 4, 2026

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

Updated under an hour ago (Oct 27, 2026, 12:50 AM ET)

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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.

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Exploited in the last 30 days

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): CWE-20
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 19, 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

References

https://git.kernel.org/stable/c/c7498f9bc390479ccfad7c7f2332237ff4945b03	patch
https://git.kernel.org/stable/c/611ef4bd9c73d9e6d87bed57a635ff1fdd8c91ea	patch
https://git.kernel.org/stable/c/6e983789b7588ee59cbf303583546c043bad8e19	patch
https://git.kernel.org/stable/c/1cc98b8887cabb1808d2f4a37cd10a7be7574771	patch
https://git.kernel.org/stable/c/b7db31a52c3862a1a32202a273a4c32e7f5f4823	patch
https://git.kernel.org/stable/c/9b75dff8446ec871030d8daf5a69e74f5fe8b956	patch
https://git.kernel.org/stable/c/7a9bc9e3f42391e4c187e099263cf7a1c4b69ff5	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-457936.html

The CVE record on cve.org NVD's entry

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.