---
id: "CVE-2026-99098"
kind: "vulnerability"
aliases: ["CVE-2026-99098"]
title: "Linux kernel dm-integrity: large tag size overflows on-stack checksum buffer"
severity: "low"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["device-mapper", "dm-integrity", "infrastructure", "kernel", "linux"]
not_affected_if: ["no-dm-integrity", "small-tag-size"]
published_at: "2026-10-26T15:16:48+00:00"
first_seen_at: "2026-10-26T16:02:26+00:00"
updated_at: "2026-10-26T16:04:02+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99098", "first_seen_at": "2026-10-26T16:02:26+00:00"}]
---

# Linux kernel dm-integrity: large tag size overflows on-stack checksum buffer

In inline mode, dm-integrity computes block checksums into a stack buffer sized HASH_MAX_DIGESTSIZE, but padding to a larger tag size writes past its end. The kernel panics on the first read, and the sources state only root can trigger it and that it is not a security bug.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-10-26T16:02:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-99098

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

dm-integrity: fix buffer overflow in inline mode with large tag size

In inline mode, dm_integrity_check and dm_integrity_inline_recheck
compute the checksum of each block into an on-stack buffer of
HASH_MAX_DIGESTSIZE bytes. integrity_sector_checksum pads its result
with zeroes up to the tag size, so if the tag size is larger than
HASH_MAX_DIGESTSIZE, the padding runs past the end of the buffer. With
CONFIG_STACKPROTECTOR the kernel panics in dm_integrity_check on the
first read.

Enlarge both buffers to hold MAX_TAG_SIZE bytes, as commit b93b6643e9b5
("dm integrity: fix a crash with unusually large tag size") did for
integrity_metadata.

Note that this is not a security bug because the buffer overflow can only
be triggered by root.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_