CVE-2023-53566

Kernel crash via unsafe nftables rbtree iteration

Published Oct 4, 2025 · Updated Oct 4, 2025

Use-after-free and NULL dereference in Linux kernel 6.2 nftables allow local users to crash the kernel through crafted rbtree set elements. nft_rbtree_gc_elem() assumes rb_prev() returns an element and continues iteration after freeing node, permitting a NULL dereference or reuse of freed memory. A local low-privileged user can reach the path through namespace-scoped nftables operations; a successful trigger crashes or wedges the kernel.

CVSS severity7.8
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free and NULL dereference in Linux kernel 6.2 nftables allow local users to crash the kernel through crafted rbtree set elements. nft_rbtree_gc_elem() assumes rb_prev() returns an element and continues iteration after freeing node, permitting a NULL dereference or reuse of freed memory. A local low-privileged user can reach the path through namespace-scoped nftables operations; a successful trigger crashes or wedges the kernel.

The record

CVE
CVE-2023-53566
Published
Oct 4, 2025
Updated
Oct 4, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=181859bdfb9734aca449512fccaee4cacce64aed <899aa5638568abf5d69de7a7bb95e4615157375b
  2. Affected versionversion=2bf1435fa19d2c58054391b3bba40d5510a5758c <ec5caa765f7f6960011c919c9aeb1467940421f6
  3. Affected versionversion=318cb24a4c3fce8140afaf84e4d45fcb76fb280b <a836be60a3aabcedcd9c79f545d409ace1f20ba6
  4. Affected versionversion=4aacf3d78424293e318c616016865380b37b9cc5 <3fa13203b6d90cc3a33af47b058739f92ab82eef
  5. Affected versionversion=6.2
  6. Affected versionversion=7ab87a326f20c52ff4d9972052d085be951c704b <b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56
  7. Affected versionversion=c9e6978e2725a7d4b6cd23b2facd3f11422c0643 <61ae320a29b0540c16931816299eb86bf2b66c08
  8. Affected versionversion=c9e6978e2725a7d4b6cd23b2facd3f11422c0643 <a337706c1fb35aac3f26b48aca80421bdbe1d33a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=181859bdfb9734aca449512fccaee4cacce64aed <899aa5638568abf5d69de7a7bb95e4615157375b; version=2bf1435fa19d2c58054391b3bba40d5510a5758c <ec5caa765f7f6960011c919c9aeb1467940421f6; version=318cb24a4c3fce8140afaf84e4d45fcb76fb280b <a836be60a3aabcedcd9c79f545d409ace1f20ba6; version=4aacf3d78424293e318c616016865380b37b9cc5 <3fa13203b6d90cc3a33af47b058739f92ab82eef; version=6.2; version=7ab87a326f20c52ff4d9972052d085be951c704b <b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56; version=c9e6978e2725a7d4b6cd23b2facd3f11422c0643 <61ae320a29b0540c16931816299eb86bf2b66c08; version=c9e6978e2725a7d4b6cd23b2facd3f11422c0643 <a337706c1fb35aac3f26b48aca80421bdbe1d33a

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo