HighCVE-2026-64563

Linux Kernel: Use After Free (CVE-2026-64563)

Published 04.08.2026Last modified 19.10.2026Sources: SUSE, HKCERT, Ubuntu, Debian, Debian LTS, Red Hat, BSI, EUVD, CVE.org, Msrc Update Guide

Public exploit

What is affected, what to do

A flaw was found in the Linux kernel. This vulnerability, known as a use-after-free, occurs in the `rhashtable` component when the system improperly handles hash table restarts.

An exploit is publicly available. Update Linux Kernel to version 6.6.151, Linux Kernel to version 6.12.103, Linux Kernel to version 6.18.42.

Affected: Linux Kernel lt 6.2..6.6.151
Linux Kernel lt 6.7..6.12.103
Linux Kernel lt 6.13..6.18.42
Linux Kernel lt 6.19..7.1.6
Linux Kernel lt 4.18..5.10.265
Linux Kernel lt 5.11..5.15.216
Linux Kernel lt 5.16..6.1.183
Fixed in: Linux Kernel 6.6.151
Linux Kernel 6.12.103
Linux Kernel 6.18.42
Linux Kernel 7.1.6
Linux Kernel 7.2
Linux Kernel 5.10.265
Linux Kernel 5.15.216
Linux Kernel 6.1.183

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Metrics

7.8

XIEM Effective CVSS

Highest available CVSS rating from NVD and vendor data.

Source: Vendor (CNA), CVSS v3

7.8

CVSS v3

Severity High on the scale from 0 to 10.

Source: SUSE, HKCERT, Ubuntu, Debian, Debian LTS, Red Hat, BSI, EUVD, CVE.org, Msrc Update Guide

0.2 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 6.1

Show all metrics

Severity: High
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 60.51 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: PoC (publicly reported)
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 7.8 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 7.8
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.2 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 6.1; Low — this CVE sits in the lower 10% of all CVEs scored today.
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 04.08.2026
CISA assessment (SSVC): Exploitation: none known · not automatable · Technical impact: total; Source: CISA Vulnrichment, as of 16 October 2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-416

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

A flaw was found in the Linux kernel. This vulnerability, known as a use-after-free, occurs in the `rhashtable` component when the system improperly handles hash table restarts. An attacker could potentially exploit this by causing the system to access memory that has already been released, which may lead to a system crash (Denial of Service) or, in more severe scenarios, allow for unauthorized code execution or information disclosure.

Source: suse_csaf, HKCERT (CC BY 3.0 HK) · HKCERT rating: medium, Ubuntu Security Notices, Debian Security Advisories, Debian LTS Advisories, redhat_csaf, BSI WID Portal, BSI CSAF, ENISA EUVD, NVD (NIST), cvelistv5, CVE.org (MITRE), Microsoft Security Update Guide

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
Linux	Linux	`5.11 – < 5.15.216` `6.2 – < 6.6.151` `5.16 – < 6.1.183` `6.13 – < 6.18.42` `4.18 – < 5.10.265` `6.7 – < 6.12.103` `—` `6.19 – < 7.1.6`	`5.15.216` `6.6.151` `6.1.183` `6.18.42` `5.10.265` `6.12.103` `7.2` `7.1.6`

Vendors and products

Affected operating systems

Affected operating systems

Linux	debian	linux	`bookworm`
Linux	debian	linux	`trixie`
Linux	ubuntu	linux	`resolute`
Linux	debian	linux-6.12	`bookworm`
Linux	ubuntu	linux-aws	`resolute`
Linux	ubuntu	linux-aws-7.0	`noble`
Linux	ubuntu	linux-azure	`resolute`
Linux	ubuntu	linux-azure-7.0	`noble`
Linux	ubuntu	linux-azure-fde	`resolute`
Linux	ubuntu	linux-azure-fde-7.0	`noble`
Linux	ubuntu	linux-gcp	`resolute`
Linux	ubuntu	linux-gcp-7.0	`noble`
Linux	ubuntu	linux-gke	`resolute`
Linux	ubuntu	linux-hwe-7.0	`noble`
Linux	ubuntu	linux-ibm	`resolute`
Linux	ubuntu	linux-nvidia	`jammy`
Linux	ubuntu	linux-nvidia-7.0	`noble`
Linux	ubuntu	linux-nvidia-bos	`resolute`
Linux	ubuntu	linux-nvidia-tegra	`jammy`
Linux	ubuntu	linux-nvidia-tegra-5.15	`focal`
Linux	ubuntu	linux-nvidia-tegra-igx	`jammy`
Linux	ubuntu	linux-oem-7.0	`resolute`
Linux	ubuntu	linux-oracle	`resolute`
Linux	ubuntu	linux-oracle-7.0	`noble`

Weakness classes (CWE)

CWE-416Use After Free
Variant
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Entry at MITRE CWE-416

Public exploit references

Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

Public exploit references

PoC-in-GitHub (nomi-sec)	CVE-2026-64563_EXP (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	13.08.2026

References & sources

git.kernel.orgstable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3euvd
git.kernel.orgstable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3euvd
git.kernel.orgstable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456euvd
git.kernel.orgstable/c/c39643ad99fea749be50615550e8f0e6d6e60694euvd
git.kernel.orgstable/c/042fda5c088015f18838e5c692659a7be60aeb26euvd
git.kernel.orgstable/c/ba510b5e9fe396497d31162acb579f210adfe6c8euvd
git.kernel.orgstable/c/a0406c40c6638c5ae50257db6297b2fba6c9ba16euvd
git.kernel.orgstable/c/0955b65c2b47c30b439e2cf1b1e375073aa0413aeuvd

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

19.10.2026Record modifiedCISA ADP
Weakness type: CWE-416
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
Weakness type (CWE) added
—
CWE-416
Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Individual changes of this event as published by NVD
Type	Action	Before	After
Weakness type (CWE)	added	—	CWE-416

16.10.2026Record modifiedLinux

New references:

and 4 more references

Show 16 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://git.kernel.org/stable/c/042fda5c088015f18838e5c692659a7be60aeb26
Reference	added	—	https://git.kernel.org/stable/c/0955b65c2b47c30b439e2cf1b1e375073aa0413a
Reference	added	—	https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3
Reference	added	—	https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3
Reference	added	—	https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456
Reference	added	—	https://git.kernel.org/stable/c/a0406c40c6638c5ae50257db6297b2fba6c9ba16
Reference	added	—	https://git.kernel.org/stable/c/ba510b5e9fe396497d31162acb579f210adfe6c8
Reference	added	—	https://git.kernel.org/stable/c/c39643ad99fea749be50615550e8f0e6d6e60694
Reference	removed	https://git.kernel.org/stable/c/042fda5c088015f18838e5c692659a7be60aeb26	—
Reference	removed	https://git.kernel.org/stable/c/0955b65c2b47c30b439e2cf1b1e375073aa0413a	—
Reference	removed	https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3	—
Reference	removed	https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3	—
Reference	removed	https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456	—
Reference	removed	https://git.kernel.org/stable/c/a0406c40c6638c5ae50257db6297b2fba6c9ba16	—
Reference	removed	https://git.kernel.org/stable/c/ba510b5e9fe396497d31162acb579f210adfe6c8	—
Reference	removed	https://git.kernel.org/stable/c/c39643ad99fea749be50615550e8f0e6d6e60694	—

Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

16.10.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: none known, automatable: no

Show the original change

Individual changes of this event as published by NVD
Type	Action	Before	After
SSVC assessment	added	—	{"id":"CVE-2026-64563","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:42:55.008845Z"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

19.08.2026Record modifiedLinux

New references:

Show 4 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://git.kernel.org/stable/c/0955b65c2b47c30b439e2cf1b1e375073aa0413a
Reference	added	—	https://git.kernel.org/stable/c/a0406c40c6638c5ae50257db6297b2fba6c9ba16
Reference	added	—	https://git.kernel.org/stable/c/ba510b5e9fe396497d31162acb579f210adfe6c8
Affected versions (publisher)	changed	Linux, Linux	Linux, Linux

Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

17.08.2026Record modifiedLinux
1 individual change: Affected versions (publisher)
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
Affected versions (publisher) changed
Linux, Linux
Linux, Linux
Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	changed	Linux, Linux	Linux, Linux

Show 3 older changes

09.08.2026Record modifiedLinux

New references:

Show 3 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://git.kernel.org/stable/c/042fda5c088015f18838e5c692659a7be60aeb26
Reference	added	—	https://git.kernel.org/stable/c/c39643ad99fea749be50615550e8f0e6d6e60694
Affected versions (publisher)	changed	Linux, Linux	Linux, Linux

Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

08.08.2026Record modifiedLinux
CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
CVSS added
—
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Individual changes of this event as published by NVD
Type	Action	Before	After
CVSS	added	—	AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

04.08.2026ReceivedLinux

Description added or changed

New references:

Show 5 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Linux, Linux
Description	added	—	In the Linux kernel, the following vulnerability has been resolved: rhashtable: clear stale iter->p on table restart rhashtable_walk_start_check() has two restart paths when resuming a walk. When iter->walker.tbl is valid, it re-validates iter->p against the table and sets iter->p = NULL if the object is gone. When iter->walker.tbl is NULL (table was freed during resize), it resets slot and skip but forgets to clear iter->p. rhashtable_walk_next() then dereferences the stale iter->p, reading freed memory. This is a use-after-free. Any caller that does multi-fragment rhashtable walks across walk_stop/walk_start boundaries is affected. Concrete cases include netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC (tipc_nl_sk_walk in net/tipc/socket.c). Crash stack (netlink_diag): BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0 Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080) Call Trace: rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016) __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122) netlink_diag_dump+0xc2/0x240 netlink_dump+0x5bc/0x1270 netlink_recvmsg+0x7a3/0x980 sock_recvmsg+0x1bc/0x200 __sys_recvfrom+0x1d4/0x2c0
Reference	added	—	https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3
Reference	added	—	https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3
Reference	added	—	https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456

Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Linked advisories

AI found Linux kernel bugs that remained undetected for decadesCSO Online12.11.2026

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<a href="https://intel.neosec.eu/en/cve/CVE-2026-64563"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-64563.svg?lang=en" alt="CVE-2026-64563 – NEOSEC Intel" height="20"></a>