CVE-2026-46107

High

In the Linux kernel, the following vulnerability has been resolved: dm-thin: fix metadata refcount underflow There's a bug in dm-thin in the function rebalance_children. If the internal btree node has one entry, the code tries to copy all btree entries from the node's child to the node itself and then decrement the child's reference count. If the child node is shared (it has reference count > 1), we won't free it, so there would be two pointers to each of the grandchildren nodes. But the reference counts of the grandchildren is not increased, thus the reference count doesn't match the number of pointers that point to the grandchildren. This results in "device mapper: space map common: unable to decrement block" errors. Fix this bug by incrementing reference counts on the grandchildren if the btree node is shared.

Package Linux Kernel
Published 2026-05-28
Last modified 2026-06-01
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 3.2 and later are affected. Fixed in 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1-rc2 and their respective stable series.

Affected from
≥ 3.2
Fixed in
✓ 5.15.209 5.15.x ✓ 6.1.175 6.1.x ✓ 6.6.140 6.6.x ✓ 6.12.88 6.12.x ✓ 6.18.30 6.18.x ✓ 7.0.7 7.0.x ✓ 7.1-rc2

References

The following references provide additional information about CVE-2026-46107 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

7 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-46107?

    CVE-2026-46107 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 3.2 onward and has been patched in 5.15.209, 6.1.175, 6.6.140 and others. CVE-2026-46107 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-46107?

    CVE-2026-46107 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-46107?

    Yes — CVE-2026-46107 has been patched. Fixed versions include 5.15.209, 6.1.175, 6.6.140 and others. If you are running Linux kernel 3.2 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-46107 actively exploited?

    No — CVE-2026-46107 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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