CVE-2023-53566: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_rbtree: fix null deref on element insertion There is no guarantee that rb_prev() will not return NULL in nft_rbtree_gc_elem(): general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] nft_add_set_elem+0x14b0/0x2990 nf_tables_newsetelem+0x528/0xb30 Furthermore, there is a possible use-after-free while iterating, 'node' can be free'd so we need to cache the next value to use.

Affected products

• Linux Linux Kernel: from 5.10.166, before 5.10.181 (fixed in 5.10.181); from 5.15.91, before 5.15.113 (fixed in 5.15.113); from 6.1.9, before 6.1.30 (fixed in 6.1.30); from 6.2.1, before 6.3.4 (fixed in 6.3.4); version 6.2 only; version 6.4 only

Published 2025-10-04. Last modified 2026-08-04.