Linux vulnerability

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.

Published 25 Jun 2026Updated 8 Sep 20267 sources
CVSS 5.5

What happened

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.

Affected versions

Linux: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before 3747de241a66ef2c7032d2cc2b826a47c5fa0f6a (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before ecfe9171b26ae3eed0cd8bab7a943e9e2c9e51ba (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before 82b3e7ce10c53fc12aab8904745603efc74f8c07 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before ede69b8f6670600e534591664584f810d7c385f9 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before c68517a3e18e20997808821c5559d0cba4d776c1 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before 5d39580f68e6ddeedd15e587282207489dfb3da2 (git); 2.6.12; V3.1.6 through before * (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.