High severity · published Feb 4, 2026
CVE-2026-23083
fou: Don't allow 0 for FOU_ATTR_IPPROTO.
7.8
CVSS
0.2%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 5% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
3.18 before 5.10.249; 5.11 before 5.15.199; 5.16 before 6.1.162; 6.2 before 6.6.122; 6.7 before 6.12.68; 6.13 before 6.18.8; +6 more · source: NVD
LI
Linux · Linux
23461551c00628c3f3fe9cf837bf53cf8f212b63 before c7498f9bc390479ccfad7c7f2332237ff4945b03; 23461551c00628c3f3fe9cf837bf53cf8f212b63 before 611ef4bd9c73d9e6d87bed57a635ff1fdd8c91ea; 23461551c00628c3f3fe9cf837bf53cf8f212b63 before 6e983789b7588ee59cbf303583546c043bad8e19; 23461551c00628c3f3fe9cf837bf53cf8f212b63 before 1cc98b8887cabb1808d2f4a37cd10a7be7574771; 23461551c00628c3f3fe9cf837bf53cf8f212b63 before b7db31a52c3862a1a32202a273a4c32e7f5f4823; 23461551c00628c3f3fe9cf837bf53cf8f212b63 before 9b75dff8446ec871030d8daf5a69e74f5fe8b956; +2 more · source: vendor
SS
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7; V3.1.6; V3.1.7 · source: CISA
SS
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7; V3.1.6; V3.1.7 · source: CISA
SS
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23083
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-23083
Patch
https://git.kernel.org/stable/c/1cc98b8887cabb1808d2f4a37cd10a7be7574771
Patch
https://git.kernel.org/stable/c/611ef4bd9c73d9e6d87bed57a635ff1fdd8c91ea
Patch
https://git.kernel.org/stable/c/6e983789b7588ee59cbf303583546c043bad8e19
Patch
https://git.kernel.org/stable/c/7a9bc9e3f42391e4c187e099263cf7a1c4b69ff5
Patch
https://git.kernel.org/stable/c/9b75dff8446ec871030d8daf5a69e74f5fe8b956
Patch
https://git.kernel.org/stable/c/b7db31a52c3862a1a32202a273a4c32e7f5f4823
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