CVE Catalog

CVE-2026-97598

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, the IPv4 FIB subsystem has a vulnerability of unbounded table ID probing during automatic allocation. This can lead to long RTNL hold times, causing performance issues.

Risk Assessment

A local attacker could exploit this to cause prolonged RTNL blocking, leading to denial of service (DoS) for other network operations.

Recommendation

Apply the kernel patch that bounds automatic table ID allocation to 4096 to keep RTNL hold time bounded.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: bound automatic table ID allocation fib_empty_table() probes every table ID from 1 until it finds a free one. IPv4 tables are stored in a 256-bucket hash table, so a dense set of IDs makes each probe walk a growing hash chain while RTNL is held. Automatic table assignment ("ip rule ... table 0") is an IPv4-only legacy path. Bound the automatically allocated ID to 4096 so the RTNL hold stays bounded, without changing lookups of explicitly specified table IDs. This changes user-visible behavior. A table-0 rule previously received the lowest free ID in 1..RT_TABLE_MAX (0xFFFFFFFF). After this patch the search stops at 4096 and the rule add fails with ENOBUFS if that range is fully occupied. Explicit table IDs above 4096 remain usable. The automatic path is unused in practice: it is IPv4-only, not documented by ip-rule, uncovered by kernel selftests, and both NetworkManager and systemd refuse table 0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS