CVE-2026-46107
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-191
- Record status
- Modified
Affected
- Linux Kernel < 5.10.259
- Linux Kernel < 5.15.209
- Linux Kernel < 6.1.175
- Linux Kernel < 6.6.140
- Linux Kernel < 6.12.88
- Linux Kernel < 6.18.30
- Linux Kernel < 7.0.7
- Linux Kernel 7.1
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-46107.md and follow it. Check whether this project is affected by CVE-2026-46107. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/09a65adc7d8bbfce06392cb6d375468e2728ead5
- https://git.kernel.org/stable/c/12161e03d33afce781f68fa11cc6060538862fad
- https://git.kernel.org/stable/c/323d252a4a378834e4fe68298ca61cfc5dd3a460
- https://git.kernel.org/stable/c/5ec0debbcfd43596e32c1239e993de06a704e04c
- https://git.kernel.org/stable/c/85311a585a26640760cd0f3349ab9f2905691044
- https://git.kernel.org/stable/c/b719d12cb94df345e9ad2715fd0abe9afcaeb111
- https://git.kernel.org/stable/c/f06f6aededd792a754cd677c02b3d3016d868c2c
- https://git.kernel.org/stable/c/f49b41c9eb7c6ff00df27cd49cea210abbadd8ad
References
- https://git.kernel.org/stable/c/09a65adc7d8bbfce06392cb6d375468e2728ead5
- https://git.kernel.org/stable/c/12161e03d33afce781f68fa11cc6060538862fad
- https://git.kernel.org/stable/c/323d252a4a378834e4fe68298ca61cfc5dd3a460
- https://git.kernel.org/stable/c/5ec0debbcfd43596e32c1239e993de06a704e04c
- https://git.kernel.org/stable/c/85311a585a26640760cd0f3349ab9f2905691044
- https://git.kernel.org/stable/c/b719d12cb94df345e9ad2715fd0abe9afcaeb111
- https://git.kernel.org/stable/c/f06f6aededd792a754cd677c02b3d3016d868c2c
- https://git.kernel.org/stable/c/f49b41c9eb7c6ff00df27cd49cea210abbadd8ad
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html