CVE-2026-89559: Linux Vulnerability (CVSS 7.8)

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().

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.16%

5.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 564e871aa66f548a947b23808d3140f326381f0c, < b4975f2ff6c82adc24ae547f029f82530ba43cfe; >= 564e871aa66f548a947b23808d3140f326381f0c, < 6030597ec683d1e5b46445f888bb5c7776b5a0c4; >= 564e871aa66f548a947b23808d3140f326381f0c, < 1c391696d2791f82ae462e11da9a0d96f90b240c; >= 564e871aa66f548a947b23808d3140f326381f0c, < 93967bfb17dab66642c57e609c99e1a91fe11278; >= 564e871aa66f548a947b23808d3140f326381f0c, < e057efcc9c71d90099d9ee00bed0748d0e9fd586; >= 564e871aa66f548a947b23808d3140f326381f0c, < 09e649117c54b7e1c004f22eaa19efbadd9ac856; >= 564e871aa66f548a947b23808d3140f326381f0c, < 69a734359639fca16a0dd73ab17a34943e76c68b; >= 564e871aa66f548a947b23808d3140f326381f0c, < 037770686126155eafc44501312989e2837b9659
Linux	Linux	4.13

References

Timeline

Published: Sep 11, 2026
Last Modified: Sep 14, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-89559?

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().

How severe is CVE-2026-89559?

CVE-2026-89559 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2026-89559?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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