Medium 5.5Published Jun 25, 2026

CVE-2026-53236tcp: restrict SO_ATTACH_FILTER to priv users

Updated under an hour ago (Oct 26, 2026, 1:40 PM ET)

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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: tcp: restrict SO_ATTACH_FILTER to priv users This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets to users with CAP_NET_ADMIN capability. This blocks potential side-channel attack where an unprivileged application attaches a filter to leak TCP sequence/acknowledgment numbers.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 3747de241a66ef2c7032d2cc2b826a47c5fa0f6a; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before ecfe9171b26ae3eed0cd8bab7a943e9e2c9e51ba; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 82b3e7ce10c53fc12aab8904745603efc74f8c07; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before ede69b8f6670600e534591664584f810d7c385f9; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before c68517a3e18e20997808821c5559d0cba4d776c1; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 5d39580f68e6ddeedd15e587282207489dfb3da2	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 SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	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 2.6.12.1 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.94; from 6.13 before 6.18.36; from 6.19 before 7.0.13; 2.6.12; 2.6.12; 2.6.12; and 9 more ranges	NVD

References

References

https://git.kernel.org/stable/c/3747de241a66ef2c7032d2cc2b826a47c5fa0f6a	patch
https://git.kernel.org/stable/c/ecfe9171b26ae3eed0cd8bab7a943e9e2c9e51ba	patch
https://git.kernel.org/stable/c/82b3e7ce10c53fc12aab8904745603efc74f8c07	patch
https://git.kernel.org/stable/c/ede69b8f6670600e534591664584f810d7c385f9	patch
https://git.kernel.org/stable/c/c68517a3e18e20997808821c5559d0cba4d776c1	patch
https://git.kernel.org/stable/c/5d39580f68e6ddeedd15e587282207489dfb3da2	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-457936.html
https://cert-portal.siemens.com/productcert/html/ssa-784472.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.