CVE-2021-38185Public exploit

Code execution via pattern-file heap overwrite

Published Aug 7, 2021 · Updated Jun 9, 2025

Integer overflow in GNU cpio 2.13 and earlier allows local users to execute arbitrary code through a crafted -E pattern file. The ds_fgetstr function doubles strsize without checking for integer overflow, passes the wrapped value to ds_resize, and then writes beyond the heap buffer while read_pattern_file consumes attacker-controlled pattern data. Execution requires a victim to invoke cpio with the crafted file through the -E option, and the public proof of concept targets glibc-based cpio 2.13.

CVSS severity7.8
High
EPSS probability4.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in GNU cpio 2.13 and earlier allows local users to execute arbitrary code through a crafted -E pattern file. The ds_fgetstr function doubles strsize without checking for integer overflow, passes the wrapped value to ds_resize, and then writes beyond the heap buffer while read_pattern_file consumes attacker-controlled pattern data. Execution requires a victim to invoke cpio with the crafted file through the -E option, and the public proof of concept targets glibc-based cpio 2.13.

The record

CVE
CVE-2021-38185
Published
Aug 7, 2021
Updated
Jun 9, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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