CVE-2026-46107
dm-thin: fix metadata refcount underflow
HIGH 7.8
At a glance
- Source
- NVD
- EPSS
- EPSS 0.10 % · percentile 1 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Modified
Description
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.
Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/b719d12cb94df345e9ad2715fd0abe9afcaeb111
- https://git.kernel.org/stable/c/f49b41c9eb7c6ff00df27cd49cea210abbadd8ad
- https://git.kernel.org/stable/c/f06f6aededd792a754cd677c02b3d3016d868c2c
- https://git.kernel.org/stable/c/12161e03d33afce781f68fa11cc6060538862fad
- https://git.kernel.org/stable/c/323d252a4a378834e4fe68298ca61cfc5dd3a460
- https://git.kernel.org/stable/c/85311a585a26640760cd0f3349ab9f2905691044
- https://git.kernel.org/stable/c/5ec0debbcfd43596e32c1239e993de06a704e04c
- https://git.kernel.org/stable/c/09a65adc7d8bbfce06392cb6d375468e2728ead5
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | Linux |
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary) |
European references
- ENISA EUVD · EUVD-2026-32866
- GCVE · GCVE-0-2026-46107
CERT-FR advisories
- CERTFR-2026-AVI-1298 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1255 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1252 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1231 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1229 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1202 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1164 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1162 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1093 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1066 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0985 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0954 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0926 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0862 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0731 — Multiples vulnérabilités dans les produits Microsoft · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 3.2 < 5.10.259cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.11 < 5.15.209cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.16 < 6.1.175cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.2 < 6.6.140cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.7 < 6.12.88cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.13 < 6.18.30cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.19 < 7.0.7cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 < b719d12cb94df345e9ad2715fd0abe9afcaeb111 ; affected 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 < f49b41c9eb7c6ff00df27cd49cea210abbadd8ad ; affected 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 < f06f6aededd792a754cd677c02b3d3016d868c2c ; affected 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 < 12161e03d33afce781f68fa11cc6060538862fad ; affected 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 < 323d252a4a378834e4fe68298ca61cfc5dd3a460 ; affected 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 < 85311a585a26640760cd0f3349ab9f2905691044 |
| Linux · Linux | affected 3.2 ; unaffected 0 < 3.2 ; unaffected 5.10.259 ≤ 5.10.* ; unaffected 5.15.209 ≤ 5.15.* ; unaffected 6.1.175 ≤ 6.1.* ; unaffected 6.6.140 ≤ 6.6.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |