NULL pointer dereference in Linux

CVE-2023-53566

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (3.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 3.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-53566: held from 0.001 to 0.002.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.000

Affected products

  • Linux — versions c9e6978e2725a7d4b6cd23b2facd3f11422c0643, 6.1.30, 5.10.181
  • Linux Kernel — versions 6.2, 6.4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-53566?
CVE-2023-53566 is a high-severity vulnerability in Linux, classified under NULL Pointer Dereference. CVSS score: 7.8/10. Published 2025-10-04.
How severe is CVE-2023-53566?
High severity. CVSS v3 base score is 7.8 out of 10.