Procfs Session Handling Flaw in Linux Kernel Affects Users

CVE-2026-99280

What is CVE-2026-99280?

A vulnerability exists in the Linux kernel concerning the handling of session registrations and connection cleanups. This flaw can result in the dropping of table references while the per-session procfs entry remains active, allowing readers to hold on to the last remaining reference. When a session is registered, if there is a failure, the procfs entry should be removed before the table reference is dropped to prevent inconsistencies. During connection cleanup, sessions must be queued to ensure that their procfs readers are adequately drained after both session locks are released. Additionally, improper handling during previous-session replacement may lead to the premature destruction of the file table. The vulnerability necessitates detaching the IDR under the lock used by procfs file counters, ensuring no access to the IDR occurs during or after its destruction.

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