CVE-2025-38248 remediation guide
Linux Linux, linux kernel
In the Linux kernel, the following vulnerability has been resolved: bridge: mcast: Fix use-after-free during router port configuration The bridge maintains a global list of ports behind which a multicast router resides. The list is consulted during forwarding to ensure multicast packets are forwarded to these ports even if the ports are not member in the matching MDB entry. When per-VLAN multicast snooping is enabled, the per-port multicast context is disabled on each port and the port is removed from the global router port list: # ip link add name br1 up type bridge vlan_filtering 1 mcast_...
Identify the affected asset
Confirm whether Linux Linux, linux kernel is installed, record the deployed version and installation path, and identify exposed interfaces.
- Record the product name, package or appliance identifier, and installed version.
- Identify internet-facing, administrative, API, and internal access paths.
- Preserve the pre-change configuration and relevant service logs.
Validate the affected-version match
Compare the deployed version with the affected range: >= 2796d846d74a18cc6563e96eff8bf28c5e06f912 < 4d3c2a1d4c7c33103f1ddfdbc5cfe1ea4f6d0dcd, >= 2796d846d74a18cc6563e96eff8bf28c5e06f912 < bdced577da71b118b6ed4242ebd47f81bf54d406, >= 2796d846d74a18cc6563e96eff8bf28c5e06f912 < f05a4f9e959e0fc098046044c650acf897ea52d2, >= 2796d846d74a18cc6563e96eff8bf28c5e06f912 < 7544f3f5b0b58c396f374d060898b5939da31709, >= 5.15, >= 5.15 < 6.15.5, 6.16. Treat incomplete inventory results as unresolved.
Prioritize with independent signals
The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.
Apply supported remediation
Follow the vendor advisory or supported update path. Current fixed-version status: 6.15.5. Preserve configuration and rollback material before change.
Verify the result
Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.
- Confirm the expected version and package state.
- Run a functional health check for critical service paths.
- Review authentication, error, application, and security monitoring logs.
- Reassess exposure if the supported fix cannot be applied.
Operational boundary
This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.