Linux Kernel up to 6.18.23/6.19.13/7.0.0 Hash Calculation mfill_atomic_hugetlb privilege escalation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.4$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.18.23/6.19.13/7.0.0 and classified as critical. Affected by this vulnerability is the function mfill_atomic_hugetlb of the component Hash Calculation Handler. This manipulation causes an unknown weakness. This vulnerability is registered as CVE-2026-31575. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.18.23/6.19.13/7.0.0. Affected by this vulnerability is the function mfill_atomic_hugetlb of the component Hash Calculation Handler. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: mm/userfaultfd: fix hugetlb fault mutex hash calculation In mfill_atomic_hugetlb(), linear_page_index() is used to calculate the page index for hugetlb_fault_mutex_hash(). However, linear_page_index() returns the index in PAGE_SIZE units, while hugetlb_fault_mutex_hash() expects the index in huge page units. This mismatch means that different addresses within the same huge page can produce different hash values, leading to the use of different mutexes for the same huge page. This can cause races between faulting threads, which can corrupt the reservation map and trigger the BUG_ON in resv_map_release(). Fix this by introducing hugetlb_linear_page_index(), which returns the page index in huge page granularity, and using it in place of linear_page_index().

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-31575 since 03/09/2026. The exploitation appears to be difficult. 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 06/11/2026).

The vulnerability scanner Nessus provides a plugin with the ID 320429 (openSUSE 16 Security Update : kernel (openSUSE-SU-2026:20912-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.24, 6.19.14 or 7.0.1 eliminates this vulnerability. Applying the patch 574501ede47ac439afd67ba9812bc66722d500ba/08282b1bf74c69fc8ecd25493e7fdb5460f01290/f4689fc089765d36c026063fb22d23533e883eb6 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (320429) and CERT Bund (WID-SEC-2026-1279). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Red Hat Enterprise Linux
  • Oracle Linux
  • Open Source Linux Kernel

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.6
VulDB Meta Temp Score: 4.4

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 320429
Nessus Name: openSUSE 16 Security Update : kernel (openSUSE-SU-2026:20912-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.24/6.19.14/7.0.1
Patch: 574501ede47ac439afd67ba9812bc66722d500ba/08282b1bf74c69fc8ecd25493e7fdb5460f01290/f4689fc089765d36c026063fb22d23533e883eb6

Timelineinfo

03/09/2026 CVE reserved
04/24/2026 +45 days Advisory disclosed
04/24/2026 +0 days VulDB entry created
06/11/2026 +48 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31575 (🔒)
GCVE (CVE): GCVE-0-2026-31575
GCVE (VulDB): GCVE-100-359425
CERT Bund: WID-SEC-2026-1279 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/24/2026 18:02
Updated: 06/11/2026 14:59
Changes: 04/24/2026 18:02 (58), 05/26/2026 01:02 (7), 06/11/2026 14:59 (2)
Complete: 🔍
Cache ID: 216::103

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

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