CVE-2026-46107dm-thin: fix metadata refcount underflow
Updated under an hour ago ()
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It affects Linux and 2 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Free account, 1 product
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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 before b719d12cb94df345e9ad2715fd0abe9afcaeb111; from 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 before f49b41c9eb7c6ff00df27cd49cea210abbadd8ad; from 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 before f06f6aededd792a754cd677c02b3d3016d868c2c; from 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 before 12161e03d33afce781f68fa11cc6060538862fad; 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 builds before 323d252a4a378834e4fe68298ca61cfc5dd3a460; from 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 before 85311a585a26640760cd0f3349ab9f2905691044; 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 builds before 5ec0debbcfd43596e32c1239e993de06a704e04c; 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 builds before 09a65adc7d8bbfce06392cb6d375468e2728ead5 | CNA record |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
linux linux_kernel linux:linux_kernel | from 3.2 before 5.10.259; from 5.11 before 5.15.209; from 5.16 before 6.1.175; from 6.2 before 6.6.140; from 6.7 before 6.12.88; from 6.13 before 6.18.30; from 6.19 before 7.0.7; 7.1 | NVD |
References
- https://git.kernel.org/stable/c/b719d12cb94df345e9ad2715fd0abe9afcaeb111patch
- https://git.kernel.org/stable/c/f49b41c9eb7c6ff00df27cd49cea210abbadd8adpatch
- https://git.kernel.org/stable/c/f06f6aededd792a754cd677c02b3d3016d868c2cpatch
- https://git.kernel.org/stable/c/12161e03d33afce781f68fa11cc6060538862fadpatch
- https://git.kernel.org/stable/c/323d252a4a378834e4fe68298ca61cfc5dd3a460patch
- https://git.kernel.org/stable/c/85311a585a26640760cd0f3349ab9f2905691044patch
- https://git.kernel.org/stable/c/5ec0debbcfd43596e32c1239e993de06a704e04cpatch
- https://git.kernel.org/stable/c/09a65adc7d8bbfce06392cb6d375468e2728ead5patch
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.