Linux Kernel up to 6.12.96/6.18.39/7.1.4 s390/pkey PKEY_VERIFYPROTK buffer overflow

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.4	$0-$5k	3.39

Summaryinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 6.12.96/6.18.39/7.1.4. This impacts the function PKEY_VERIFYPROTK of the component s390/pkey. This manipulation causes buffer overflow. This vulnerability is tracked as CVE-2026-64559. The attack is restricted to local execution. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.96/6.18.39/7.1.4. It has been declared as very critical. Affected by this vulnerability is the function PKEY_VERIFYPROTK of the component s390/pkey. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: s390/pkey: Check length in PKEY_VERIFYPROTK ioctl Explicitly check the buffer length request structure provided by user-space and fail, if it exceeds the buffer size.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-64559 since 07/19/2026. The exploitation appears to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/29/2026).

Upgrading to version 6.12.97, 6.18.40, 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch 0a9e34ccbe772b8f321388cdbdf4f22b94e513e7/693bf91d4db134f9b1c2840c8e287eee3d993bac/7e7e03848c918aa0acad5ffd75d929e3afec1554/b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970 is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
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• 6.12.39
• 6.12.40
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• 6.12.86
• 6.12.87
• 6.12.88
• 6.12.89
• 6.12.90
• 6.12.91
• 6.12.92
• 6.12.93
• 6.12.94
• 6.12.95
• 6.12.96
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
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• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.97/6.18.40/7.1.5/7.2-rc1
Patch: 0a9e34ccbe772b8f321388cdbdf4f22b94e513e7/693bf91d4db134f9b1c2840c8e287eee3d993bac/7e7e03848c918aa0acad5ffd75d929e3afec1554/b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970

Timelineinfo

07/19/2026 CVE reserved
07/29/2026 +10 days Advisory disclosed
07/29/2026 +0 days VulDB entry created
07/29/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64559 (🔒)
GCVE (CVE): GCVE-0-2026-64559
GCVE (VulDB): GCVE-100-384217

Entryinfo

Created: 07/29/2026 18:59
Changes: 07/29/2026 18:59 (59)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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