# CVE-2026-89559

## Summary

- **CVE ID:** CVE-2026-89559
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 2026

## 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().

## Affected Products

- Linux — Linux (564e871aa66f548a947b23808d3140f326381f0c)
- Linux — Linux (4.13)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.16%
- **EPSS Percentile:** 6.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._