CVE-2026-46159

Description

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.

Overview

State: PUBLISHED
Assigner (CNA): Linux
CVSS severity: high
CVSS score: 7.1 / 10
CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Effective score: 7.1 / 10 HIGH source: CNA overview
MSRC score: 5.5 / 10 MEDIUM MS rating: Moderate
CWE(s): —
Reserved: 2026-05-13
Published: 2026-05-28 09:36 UTC
Last updated: 2026-05-28 09:36 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/46xxx/CVE-2026-46159.json
Linked Threat: CVE-2026-46159 — CVE-2026-46159

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-28 10:16:31 UTC
NVD last modified: 2026-06-19 13:16:34 UTC
NVD CVSS v3.1: 4.7 / 10 MEDIUM source: nvd@nist.gov
NVD CVSS vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Exploitability subscore: 1.0 / 10
Impact subscore: 3.6 / 10
EPSS score: 0.0009 (probability of exploitation in next 30 days)
EPSS percentile: 0.69% vs all CVEs — higher = more likely to be exploited, as of 2026-07-27

NVD-assigned CWE(s): CWE-367 (differs from the CNA list above)

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-32786
Assigner: Linux
Published: May 28, 2026, 9:36:14 AM
Updated: Jun 19, 2026, 11:59:41 AM
EUVD base score: 0.0 / 10
EUVD-reported EPSS: 0.0900
Vendors: Linux
Products: Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <d69a4a6813fdba7c4cc3695a7e843842b240790d)

Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <f5ee467b56764964027c361641f64953fc0f8f9a)

Linux (patch: 7.1)

Linux (patch: 6.1.176)

Linux (patch: 7.0.7)

Linux (patch: 5.10.259)

Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <d09d67d5de577cedae3de9497dff217e0ac8b641)

Linux (patch: 6.12.90)

Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <973e57c726c1f8e77259d1c8e519519f1e9aea77)

Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <5d12e0ab009ade48c1bff9324fd9bea2c773d088)

Linux (patch: 6.6.140)

Linux (patch: 6.18.32)

Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <f407aad350bdea4db300c47433573b7a41630d33)

Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <d8224b1be6627c6c3b204bfb264508d27c65ac44)

Linux (2.6.34)

Linux (patch: 5.15.210)

Linux (patch: 0)

Linux (7fde62bffb576d384ea49a3aed3403d5609ee5bc <4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3)
Aliases: GHSA-8m37-fqxx-cfwj

ENISA description: 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.

EUVD references (8)

Microsoft Security Response Center MSRC

Microsoft's vendor-authoritative record from the Security Update Guide — its own CVSS score, impact, severity rating, exploit assessment, and KB-article fixes. Refreshed 2026-11-05 03:38 UTC (source: CVRF).

MS severity: Moderate
MS CVSS base score: 5.5 / 10 (temporal 5.1)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U
Release: 2026-May

Microsoft remediations / KB articles (2)

CBL-Mariner Releases — Vendor Fix / Security Update (fixed build 6.6.141.1-1)
https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade — None Available / CBL-Mariner Releases

Affected products (2)

Vendor	Product	Versions	Platforms
Linux	Linux	`7fde62bffb576d384ea49a3aed3403d5609ee5bc` (affected), `7fde62bffb576d384ea49a3aed3403d5609ee5bc` (affected), `7fde62bffb576d384ea49a3aed3403d5609ee5bc` (affected), `7fde62bffb576d384ea49a3aed3403d5609ee5bc` (affected), `7fde62bffb576d384ea49a3aed3403d5609ee5bc` (affected)	—
Linux	Linux	`2.6.34` (affected), `0` (unaffected), `6.6.140` (unaffected), `6.12.90` (unaffected), `6.18.32` (unaffected), `7.0.7` (unaffected), `7.1-rc1` (unaffected)	—

Affected products — CPE 2.3 (8) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.34:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.34:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.34:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.34:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.34:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.34:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.34:rc7:*:*:*:*:*:*

Vendor references (5)

References embedded in the original CVE record by the assigning CNA.

MITRE references (3) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

Web references (10)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

None Available msrc
MSRC update guide: CVE-2026-46159 msrc
https://nvd.nist.gov/vuln/detail/CVE-2026-46159 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-46159 tenable:www.cve.org
https://git.kernel.org/stable/c/4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3 tenable:git.kernel.org
https://www.first.org/epss/ tenable:www.first.org
https://git.kernel.org/stable/c/5d12e0ab009ade48c1bff9324fd9bea2c773d088 tenable:git.kernel.org
https://git.kernel.org/stable/c/973e57c726c1f8e77259d1c8e519519f1e9aea77 tenable:git.kernel.org
https://git.kernel.org/stable/c/d09d67d5de577cedae3de9497dff217e0ac8b641 tenable:git.kernel.org
https://git.kernel.org/stable/c/f5ee467b56764964027c361641f64953fc0f8f9a tenable:git.kernel.org

NVD-tagged references (8)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://git.kernel.org/stable/c/4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/5d12e0ab009ade48c1bff9324fd9bea2c773d088 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/973e57c726c1f8e77259d1c8e519519f1e9aea77 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/d09d67d5de577cedae3de9497dff217e0ac8b641 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/f5ee467b56764964027c361641f64953fc0f8f9a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/d69a4a6813fdba7c4cc3695a7e843842b240790d 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/d8224b1be6627c6c3b204bfb264508d27c65ac44 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/f407aad350bdea4db300c47433573b7a41630d33 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Remediations (17)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Security Updates - Red Hat Customer Portal

web:access.redhat.com

Learn about our open source products, services, and company. You are here

2026-06-04 00:01 UTC
Microsoft Patch Tuesday May 2026 - 120 Vulnerabilities Fixed, Including ...

web:cybersecuritynews.com

Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.

2026-06-04 00:01 UTC
GitHub - 0xBlackash/CVE-2026-41091: CVE-2026-41091

web:github.com

CVE ID: CVE - 2026 -41091 Vulnerability Type: Improper Link Resolution Before File Access (CWE-59 - Link Following) Affected Component: Microsoft Malware Protection Engine Root Cause: Defender fails to properly resolve links/junctions during cloud-tagged file remediation /rollback, allowing redirection of privileged writes. Impact: Local authenticated attacker can escalate from standard user to ...

2026-06-04 00:01 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-06-04 00:01 UTC
March 13, 2026—Hotpatch KB5084597 (OS Builds 26200.7982 and 26100.7982 ...

web:support.microsoft.com

This update for Windows 11, version 25H2 and 24H2 (KB5084597) incudes security improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates. To view the ...

2026-06-04 00:01 UTC
Landing Page | ServiceNow Common Vulnerabilities & Exposures (CVE ...

web:support.servicenow.com

Overview The advisories below document publicly disclosed Common Vulnerabilities and Exposures ( CVEs ) in the Now Platform by ServiceNow. Because ServiceNow uses various methods to communicate vulnerability information, patches, and other fixes, customers should review family, security patch , and hotfix release notes, which are available at https://docs.servicenow.com, for a complete list of ...

2026-06-04 00:01 UTC
Critical Patch Updates, Critical Security Patch Updates ... - Oracle

web:www.oracle.com

Critical Security Patch Updates Critical Security Patch Updates provide security patches for supported Oracle on-premises products. A Critical Security Patch Update provides targeted, high-priority security fixes in a smaller, more focused format, making them easier to apply with minimal disruption.

2026-06-04 00:01 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-06-04 00:01 UTC
VirusTotal - Home

web:www.virustotal.com

VirusTotal is a platform for scanning files and URLs for viruses, malware, and other threats using multiple antivirus engines.

2026-06-04 00:01 UTC
Patch Tuesday June 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's June 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-06-04 00:01 UTC
Microsoft Confirms Defender RoguePlanet 0-Day Exploit and Working to ...

web:cybersecuritynews.com

Microsoft has officially acknowledged a critical zero-day vulnerability in Microsoft Defender, publicly dubbed "RoguePlanet," and confirmed it is actively developing a security patch to address the flaw.

2026-06-19 02:28 UTC
Nvd - Cve-2026-24159

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-06-19 02:28 UTC
Microsoft Patches 59 Vulnerabilities Including Six Actively Exploited ...

web:thehackernews.com

Microsoft patches 59 vulnerabilities, including six actively exploited zero-days, with CISA mandating urgent federal remediation .

2026-06-19 02:28 UTC
February's Patch Tuesday release fixes 59 flaws ... - Computerworld

web:www.computerworld.com

Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. The company's Patch Tuesday release for February ...

2026-06-19 02:28 UTC
Microsoft is working on a patch for 'YellowKey ... - Computerworld

web:www.computerworld.com

Microsoft says it is considering a patch for a zero-day vulnerability, dubbed YellowKey, that allows attackers with access to a Windows device to bypass Bitlocker encryption protection and read ...

2026-06-19 02:28 UTC
Microsoft Confirms It Is Urgently Working On Patch For ... - LinkedIn

web:www.linkedin.com

Microsoft has confirmed that it is developing a security update to address a newly disclosed zero-day vulnerability in Microsoft Defender, following the public release of exploit code that ...

2026-06-19 02:28 UTC
Microsoft working on a fix for RoguePlanet, a flaw that grants full PC ...

web:www.malwarebytes.com

Microsoft says it's working on a fix for an unpatched Defender vulnerability that can give attackers the highest level of access on Windows.

2026-06-19 02:28 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-46159.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/ioctl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f5ee467b56764964027c361641f64953fc0f8f9a",
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            },
            {
              "lessThan": "4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3",
              "status": "affected",
              "version": "7fde62bffb576d384ea49a3aed3403d5609ee5bc",
              "versionType": "git"
            },
            {
              "lessThan": "5d12e0ab009ade48c1bff9324fd9bea2c773d088",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "d09d67d5de577cedae3de9497dff217e0ac8b641",
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              "lessThan": "973e57c726c1f8e77259d1c8e519519f1e9aea77",
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          "versions": [
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            },
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              "lessThan": "2.6.34",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
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            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.32",
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            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak\n\nbtrfs_ioctl_space_info() has a TOCTOU race between two passes over the\nblock group RAID type lists. The first pass counts entries to determine\nthe allocation size, then the second pass fills the buffer. The\ngroups_sem rwlock is released between passes, allowing concurrent block\ngroup removal to reduce the entry count.\n\nWhen the second pass fills fewer entries than the first pass counted,\ncopy_to_user() copies the full alloc_size bytes including trailing\nuninitialized kmalloc bytes to userspace.\n\nFix by copying only total_spaces entries (the actually-filled count from\nthe second pass) instead of alloc_size bytes, and switch to kzalloc so\nany future copy size mismatch cannot leak heap data."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-28T09:36:14.676Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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        },
        {
          "url": "https://git.kernel.org/stable/c/973e57c726c1f8e77259d1c8e519519f1e9aea77"
        }
      ],
      "title": "btrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46159",
    "datePublished": "2026-05-28T09:36:14.676Z",
    "dateReserved": "2026-05-13T15:03:33.102Z",
    "dateUpdated": "2026-05-28T09:36:14.676Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}