IT

Tracker / CVE-2026-46107

CVE-2026-46107

High 7.8

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.

Affected products and versions

linux linux_kernel
linux linux_kernel · 3.2 → 5.10.259
linux linux_kernel · 5.11 → 5.15.209
linux linux_kernel · 5.16 → 6.1.175
linux linux_kernel · 6.13 → 6.18.30
linux linux_kernel · 6.19 → 7.0.7
linux linux_kernel · 6.2 → 6.6.140
linux linux_kernel · 6.7 → 6.12.88

Analysis

This page is not indexable yet.Until it carries original analysis — what it actually exposes, how to check in two minutes whether a system was touched, what to do if it was — the page stays noindex. The database decides that, not the template.

References