Linux Kernel up to 6.6.139/6.12.89/6.18.31/7.0.6 btrfs btrfs_ioctl_space_info toctou

CVSS Meta Temp Score
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CTI Interest Score
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4.6$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.6.139/6.12.89/6.18.31/7.0.6. Affected is the function btrfs_ioctl_space_info of the component btrfs. The manipulation results in toctou. This vulnerability is cataloged as CVE-2026-46159. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.139/6.12.89/6.18.31/7.0.6. It has been classified as critical. Affected is the function btrfs_ioctl_space_info of the component btrfs. The manipulation with an unknown input leads to a toctou vulnerability. CWE is classifying the issue as CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak btrfs_ioctl_space_info() has a TOCTOU race between two passes over the block group RAID type lists. The first pass counts entries to determine the allocation size, then the second pass fills the buffer. The groups_sem rwlock is released between passes, allowing concurrent block group removal to reduce the entry count. When the second pass fills fewer entries than the first pass counted, copy_to_user() copies the full alloc_size bytes including trailing uninitialized kmalloc bytes to userspace. Fix by copying only total_spaces entries (the actually-filled count from the second pass) instead of alloc_size bytes, and switch to kzalloc so any future copy size mismatch cannot leak heap data.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-46159 since 05/13/2026. The exploitability is told to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 321697 (SUSE SLES16 Security Update : kernel (SUSE-SU-2026:22099-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.140, 6.12.90, 6.18.32, 7.0.7 or 7.1-rc1 eliminates this vulnerability. Applying the patch f5ee467b56764964027c361641f64953fc0f8f9a/4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3/5d12e0ab009ade48c1bff9324fd9bea2c773d088/d09d67d5de577cedae3de9497dff217e0ac8b641/973e57c726c1f8e77259d1c8e519519f1e9aea77 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 vulnerability database at Tenable (321697). Once again VulDB remains the best source for vulnerability data.

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: 4.6

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

NVD Base Score: 4.7
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Toctou
CWE: CWE-367 / CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 321697
Nessus Name: SUSE SLES16 Security Update : kernel (SUSE-SU-2026:22099-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.140/6.12.90/6.18.32/7.0.7/7.1-rc1
Patch: f5ee467b56764964027c361641f64953fc0f8f9a/4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3/5d12e0ab009ade48c1bff9324fd9bea2c773d088/d09d67d5de577cedae3de9497dff217e0ac8b641/973e57c726c1f8e77259d1c8e519519f1e9aea77

Timelineinfo

05/13/2026 CVE reserved
05/28/2026 +15 days Advisory disclosed
05/28/2026 +0 days VulDB entry created
06/21/2026 +24 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-46159 (🔒)
GCVE (CVE): GCVE-0-2026-46159
GCVE (VulDB): GCVE-100-366684

Entryinfo

Created: 05/28/2026 13:38
Updated: 06/21/2026 07:48
Changes: 05/28/2026 13:38 (60), 06/10/2026 12:34 (10), 06/21/2026 07:48 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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