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Vulnerabilities

Vulnerability · CVE-2026-64572

ipv4: fib: free fib_alias with kfree_rcu() on insert error path

Published Aug 5, 2026 · catalog updated Oct 22, 2026 · ipv4: fib: free fib_alias

Check if you run it

No confirmed exploitation is on record for CVE-2026-64572. EPSS is 0.20%. Act only if a listed version of ipv4: fib: free fib_alias is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (ipv4: fib: free fib_alias).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Unknown—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.20%
Remediation
Not established
Affected products
Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: free fib_alias with kfree_rcu() on insert error path fib_table_insert() publishes new_fa into the leaf's fa_list with fib_insert_alias() before calling the fib entry notifiers. When a notifier fails, the error path removes new_fa with fib_remove_alias() (hlist_del_rcu) and frees it right away with kmem_cache_free(). fib_table_lookup() walks that list under rcu_read_lock() only, so a concurrent lookup that already reached new_fa keeps reading it after the free: BUG: KASAN: slab-use-after-free in fib_table_lookup (net/ipv4/fib_trie.c:1601) Read of size 1 at addr ffff88810676d4eb by task exploit/297 Call Trace: fib_table_lookup (net/ipv4/fib_trie.c:1601) ip_route_output_key_hash_rcu (net/ipv4/route.c:2814) ip_route_output_key_hash (net/ipv4/route.c:2705) __ip4_datagram_connect (net/ipv4/datagram.c:49) udp_connect (net/ipv4/udp.c:2144) __sys_connect (net/socket.c:2167) __x64_sys_connect (net/socket.c:2173) do_syscall_64 entry_SYSCALL_64_after_hwframe which belongs to the cache ip_fib_alias of size 56 Triggering the error path needs CAP_NET_ADMIN and a registered fib notifier that can reject a route; a netdevsim device whose IPv4 FIB resource is exhausted is enough. Free new_fa with alias_free_mem_rcu(), as fib_table_delete() already does for a fib_alias removed from the trie.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Linux Kernel5.6.0 → 5.10.265; 5.11.0 → 5.15.216; 5.16.0 → 6.1.183

How to fix CVE-2026-64572

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-64572. EPSS is 0.20%. Act only if a listed version of ipv4: fib: free fib_alias is installed.

Which versions are affected?

Compare what you have installed with Kernel 5.6.0 → 5.10.265; 5.11.0 → 5.15.216; 5.16.0 → 6.1.183. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.20%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 5, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: free fib_alias with kfree_rcu() on insert error path fib_table_insert() publishes new_fa into the leaf's fa_list with fib_insert_alias() before calling the fib entry notifiers. When a notifier fails, the error path removes new_fa with fib_remove_alias() (hlist_del_rcu) and frees it right away with kmem_cache_free(). fib

  2. Oct 22, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 5.10.265; Kernel fixed in 5.15.216; Kernel fixed in 6.1.183; Kernel fixed in 6.6.148

  3. Oct 22, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 5.10.265; 5.11.0

  4. Oct 22, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: free fib_alias with kfree_rcu() on insert error path fib_table_insert() publishes new_fa into the leaf's fa_list with fib_insert_alias() before calling the fib entry notifiers. When a notifier fails, the error path removes new_fa with fib_remove_alias() (hlist_del_rcu) and frees it right away with kmem_cache_free(). fib

Sources

References

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.