CVE-2026-89559

Summary

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 Software

Weaknesses

References

• 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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