net/hsr: fix NULL pointer dereference in prp_get_untagged_frame()

These records connect through source-stated identifiers. Shared identifiers or dates alone do not establish shared exposure, root cause or applicability.

CVE-2025-68776 · Microsoft / collected KEV context

cve-program · CVE-2025-68776

• https://git.kernel.org/stable/c/3ce95a57d8a1f0e20b637cdeddaaed81831ca819
• https://git.kernel.org/stable/c/c851e43b88b40bb7c20176c51cbf4f8c8d960dd9
• https://git.kernel.org/stable/c/7be6d25f4d974e44918ba3a5d58ebb9d36879087
• https://git.kernel.org/stable/c/8f289fa12926aae44347ca7d490e216555d8f255
• https://git.kernel.org/stable/c/1742974c24a9c1f1fd2e5edca0cbaccb720b397a
• https://git.kernel.org/stable/c/6220d38a08f8837575cd8f830928b49a3a5a5095
• https://git.kernel.org/stable/c/188e0fa5a679570ea35474575e724d8211423d17

No related operational record is retained in the current change model.