HighCVE-2026-64600

Linux Kernel: Race Condition (CVE-2026-64600)

Published 23.07.2026Last modified 19.10.2026Sources: SUSE, Ubuntu, Debian LTS, BSI, CVE.org, Msrc Update Guide, Red Hat

Public exploit

What is affected, what to do

An exploit is publicly available. Update Linux Kernel to version 5.15.212, Linux Kernel to version 6.1.178, Linux Kernel to version 6.6.145.

Affected: Linux Kernel lt 4.11..5.15.212
Linux Kernel lt 5.16..6.1.178
Linux Kernel lt 6.2..6.6.145
Linux Kernel lt 6.7..6.12.96
Linux Kernel lt 6.13..6.18.39
Linux Kernel lt 6.19..7.1.4
Fixed in: Linux Kernel 5.15.212
Linux Kernel 6.1.178
Linux Kernel 6.6.145
Linux Kernel 6.12.96
Linux Kernel 6.18.39
Linux Kernel 7.1.4
Linux Kernel 7.2

Not sure whether and how you are affected? Ask a question about this vulnerability

Metrics

7.8

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: NVD, CVSS v3

7.8

CVSS v3

Severity High on the scale from 0 to 10.

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

0.5 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 40.4

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: 73.07 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: 0.5 %; 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: 40.4; High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
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: 23.07.2026
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-362

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

In the Linux kernel, the following vulnerability has been resolved: xfs: resample the data fork mapping after cycling ILOCK xfs_reflink_fill_{cow_hole,delalloc} are both presented with an inode, a data fork mapping, and a cow fork mapping. Unfortunately, these two helpers cycle the ILOCK to grab a transaction, which means that the mappings are stale as soon as we reacquire the ILOCK. Currently we refresh the cow fork mapping by re-calling xfs_find_trim_cow_extent, but we don't refresh the data fork mapping beforehand, which means that the xfs_bmap_trim_cow in that function queries the refcount btree about the wrong physical blocks and returns an inaccurate value in *shared. If *shared is now false, the directio write proceeds with a stale data fork mapping. Fix this by querying the data fork mapping if the sequence counter changes across the ILOCK cycle.

Source: suse_csaf, Ubuntu Security Notices, Debian LTS Advisories, BSI WID Portal, BSI CSAF, cvelistv5, NVD (NIST), Microsoft Security Update Guide, redhat_csaf, CVE.org (MITRE)

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	`4.11 – < 5.15.212` `6.19 – < 7.1.4` `6.2 – < 6.6.145` `6.7 – < 6.12.96` `—` `6.13 – < 6.18.39` `5.16 – < 6.1.178`	`5.15.212` `7.1.4` `6.6.145` `6.12.96` `7.2` `6.18.39` `6.1.178`
Open Source	Linux Kernel	`≥ 4.11`	—

Vendors and products

Affected operating systems

Affected operating systems

Linux	debian	linux	`bookworm`
Linux	ubuntu	linux	`noble`
Linux	debian	linux-6.1	`bullseye`
Linux	debian	linux-6.12	`bookworm`
Linux	ubuntu	linux-aws	`noble`
Linux	ubuntu	linux-aws-fips	`noble`
Linux	ubuntu	linux-azure	`noble`
Linux	ubuntu	linux-azure-fde	`noble`
Linux	ubuntu	linux-azure-fips	`noble`
Linux	ubuntu	linux-fips	`noble`
Linux	ubuntu	linux-gcp	`noble`
Linux	ubuntu	linux-gcp-fips	`noble`
Linux	ubuntu	linux-gke	`noble`
Linux	ubuntu	linux-gkeop	`noble`
Linux	ubuntu	linux-ibm	`noble`
Linux	ubuntu	linux-lowlatency	`noble`
Linux	ubuntu	linux-nvidia	`jammy`
Linux	ubuntu	linux-nvidia-tegra	`jammy`
Linux	ubuntu	linux-nvidia-tegra-5.15	`focal`
Linux	ubuntu	linux-nvidia-tegra-igx	`jammy`
Linux	ubuntu	linux-oracle	`noble`
Linux	ubuntu	linux-realtime	`noble`
Linux	linux	linux_kernel	`7.2`
Linux	linux	linux_kernel	—

Weakness classes (CWE)

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Class
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
Entry at MITRE CWE-362

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

Reference tagged as exploit	openwall.com (opens in a new tab)	PoC (publicly reported)reported, not verified	—
PoC-in-GitHub (nomi-sec)	COWSlip (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	26.09.2026
PoC-in-GitHub (nomi-sec)	CVE-2026-64600-RefluXFS-PoC (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	14.08.2026
PoC-in-GitHub (nomi-sec)	CVE-2026-64600-RefluXFS (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	09.08.2026
PoC-in-GitHub (nomi-sec)	CVE-2026-64600-Refluxfs-PoC (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	27.07.2026
PoC-in-GitHub (nomi-sec)	CVE-2026-64600 (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	26.07.2026
PoC-in-GitHub (nomi-sec)	VQ-RefluxCore (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	25.07.2026
PoC-in-GitHub (nomi-sec)	CVE-2026-64600 (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	23.07.2026
PoC-in-GitHub (nomi-sec)	CVE-2026-64600 (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	23.07.2026

References & sources

git.kernel.orgstable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075Patch
git.kernel.orgstable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9Patch
git.kernel.orgstable/c/44f891bc088958399eec27f7604928694aa35581Patch
git.kernel.orgstable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7Patch
git.kernel.orgstable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18Patch
git.kernel.orgstable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05Patch
git.kernel.orgstable/c/50f0012da1040f69a4e788cd9aed587c9a04983fPatch
cdn2.qualys.comadvisory/2026/07/22/RefluXFS.txtExploit, Third-party advisory
openwall.comlists/oss-security/2026/07/22/14Exploit, Mailing list
openwall.comlists/oss-security/2026/07/22/18Mailing list
openwall.comlists/oss-security/2026/07/22/19Mailing list
openwall.comlists/oss-security/2026/07/31/3Mailing list
openwall.comlists/oss-security/2026/08/03/4Mailing list
openwall.comlists/oss-security/2026/08/03/8Mailing list

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-362
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
Weakness type (CWE) added
—
CWE-362
Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

16.10.2026Record modifiedCVE Program

New references:

and 2 more references

Show 18 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/07/22/14
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/07/22/18
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/07/22/19
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/07/31/3
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/08/03/4
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/08/03/8
Reference	removed	http://www.openwall.com/lists/oss-security/2026/07/22/14	—
Reference	removed	http://www.openwall.com/lists/oss-security/2026/07/22/18	—
Reference	removed	http://www.openwall.com/lists/oss-security/2026/07/22/19	—
Reference	removed	http://www.openwall.com/lists/oss-security/2026/07/31/3	—
Reference	removed	http://www.openwall.com/lists/oss-security/2026/08/03/4	—
Reference	removed	http://www.openwall.com/lists/oss-security/2026/08/03/8	—
Reference type	removed	http://www.openwall.com/lists/oss-security/2026/07/22/14 Types: Exploit, Mailing List	—
Reference type	removed	http://www.openwall.com/lists/oss-security/2026/07/22/18 Types: Mailing List	—
Reference type	removed	http://www.openwall.com/lists/oss-security/2026/07/22/19 Types: Mailing List	—
Reference type	removed	http://www.openwall.com/lists/oss-security/2026/07/31/3 Types: Mailing List	—
Reference type	removed	http://www.openwall.com/lists/oss-security/2026/08/03/4 Types: Mailing List	—
Reference type	removed	http://www.openwall.com/lists/oss-security/2026/08/03/8 Types: Mailing List	—

Source identifier: af854a3a-2127-422b-91ae-364da2661108

16.10.2026Record modifiedLinux

New references:

and 4 more references

Show 24 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt
Reference	added	—	https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9
Reference	added	—	https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7
Reference	added	—	https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581
Reference	added	—	https://git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f
Reference	added	—	https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05
Reference	added	—	https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18
Reference	added	—	https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075
Reference	removed	https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt	—
Reference	removed	https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9	—
Reference	removed	https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7	—
Reference	removed	https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581	—
Reference	removed	https://git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f	—
Reference	removed	https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05	—
Reference	removed	https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18	—
Reference	removed	https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075	—
Reference type	removed	https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt Types: Exploit, Third Party Advisory	—
Reference type	removed	https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075 Types: Patch	—

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-2026-64600","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:43:31.132977Z"}

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

18.08.2026Initial analysis by NVDNVD

Newly listed as affected:

Linux Kernel (5.16 – before 6.1.178; 6.2 – before 6.6.145; 6.7 – before 6.12.96; 6.13 – before 6.18.39; 6.19 – before 7.1.4; 4.11 – before 5.15.212; 3 individual versions)

Weakness type: CWE-362

New references:

and 8 more references

Show 16 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Weakness type (CWE)	added	—	CWE-362
Product configuration	added	—	OR cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 5.16 up to (excluding) 6.1.178 cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 6.2 up to (excluding) 6.6.145 cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 6.7 up to (excluding) 6.12.96 cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 6.13 up to (excluding) 6.18.39 cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 6.19 up to (excluding) 7.1.4 cpe:2.3:o:linux:linux_kernel:7.2:rc1::::::* cpe:2.3:o:linux:linux_kernel:7.2:rc2::::::* cpe:2.3:o:linux:linux_kernel:7.2:rc3::::::* cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 4.11 up to (excluding) 5.15.212
Reference type	added	—	kernel.org: https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt Types: Exploit, Third Party Advisory
Reference type	added	—	kernel.org: https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9 Types: Patch
Reference type	added	—	kernel.org: https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7 Types: Patch
Reference type	added	—	kernel.org: https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581 Types: Patch
Reference type	added	—	kernel.org: https://git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f Types: Patch
Reference type	added	—	kernel.org: https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05 Types: Patch
Reference type	added	—	kernel.org: https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18 Types: Patch
Reference type	added	—	kernel.org: https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075 Types: Patch
Reference type	added	—	CVE: http://www.openwall.com/lists/oss-security/2026/07/22/14 Types: Exploit, Mailing List
Reference type	added	—	CVE: http://www.openwall.com/lists/oss-security/2026/07/22/18 Types: Mailing List
Reference type	added	—	CVE: http://www.openwall.com/lists/oss-security/2026/07/22/19 Types: Mailing List
Reference type	added	—	CVE: http://www.openwall.com/lists/oss-security/2026/07/31/3 Types: Mailing List
Reference type	added	—	CVE: http://www.openwall.com/lists/oss-security/2026/08/03/4 Types: Mailing List
Reference type	added	—	CVE: http://www.openwall.com/lists/oss-security/2026/08/03/8 Types: Mailing List

Source identifier: nvd@nist.gov

Show 6 older changes

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
03.08.2026Record modifiedCVE Program
New references:
- http://www.openwall.com/lists/oss-security/2026/08/03/8
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
Reference added
—
http://www.openwall.com/lists/oss-security/2026/08/03/8
Source identifier: af854a3a-2127-422b-91ae-364da2661108
03.08.2026Record modifiedCVE Program
New references:
- http://www.openwall.com/lists/oss-security/2026/08/03/4
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
Reference added
—
http://www.openwall.com/lists/oss-security/2026/08/03/4
Source identifier: af854a3a-2127-422b-91ae-364da2661108

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

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/08/03/8

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/08/03/4

24.07.2026Record 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/50f0012da1040f69a4e788cd9aed587c9a04983f
Reference	added	—	https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05
Reference	added	—	https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18
Affected versions (publisher)	changed	Linux, Linux	Linux, Linux

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

24.07.2026Record modifiedLinux
New references:
- https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
Reference added
—
https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt
Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

23.07.2026Record modifiedCVE Program

New references:

Show 3 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/07/22/14
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/07/22/18
Reference	added	—	http://www.openwall.com/lists/oss-security/2026/07/22/19

Source identifier: af854a3a-2127-422b-91ae-364da2661108

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