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Fencer Vulns
high 7.8

CVE-2021-38185 json

GNU cpio through 2.13 allows attackers to execute arbitrary code via a crafted pattern file, because of a dstring.c ds_fgetstr integer over…

published 2021-08-07 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-24655

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.2%
EPSS 4.2% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

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.

Patch / fix

  • cpio Debian 14, Debian 13, Debian 12 2.13+dfsg-5

debian advisories DEBIAN-CVE-2021-38185

  • cpio Ubuntu 18.04 LTS 2.12+dfsg-6ubuntu0.18.04.4
  • cpio Ubuntu 20.04 LTS 2.13+dfsg-2ubuntu0.3
  • cpio Ubuntu 22.04 LTS 2.13+dfsg-4ubuntu4
  • cpio Ubuntu Pro 14.04 LTS 2.11+dfsg-1ubuntu1.2+esm2
  • cpio Ubuntu Pro 16.04 LTS 2.11+dfsg-5ubuntu1.1+esm1

ubuntu advisories UBUNTU-CVE-2021-38185

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • cpio RHEL 8 2.12-11.el8

red hat advisories RHSA-2022:1991

  • cpio SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +10 more 2.11-36.15.1
  • cpio SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 2.9-75.81.14.1
  • cpio SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +13 more 2.12-3.9.1
  • cpio SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +10 more 2.11-36.12.1
  • cpio SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +10 more 2.11-36.9.1
  • cpio SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 2.9-75.81.8.1

suse advisories SUSE-SU-2021:2808-1SUSE-SU-2021:14788-1SUSE-RU-2021:2780-1SUSE-RU-2021:2779-1SUSE-SU-2021:2686-1SUSE-SU-2021:14777-1

  • cpio openSUSE Tumbleweed 2.13-3.3

opensuse advisories openSUSE-SU-2024:10697-1

  • cpio AlmaLinux 8 2.12-11.el8

almalinux advisories ALSA-2022:1991

  • cpio Rocky Linux 8 2.12-11.el8

rocky linux advisories RLSA-2022:1991

  • cpio Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 2.13-r2

alpine advisories ALPINE-CVE-2021-38185

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • cpio CBL-Mariner 2.0 2.13-4

azure linux advisories AZL-6357

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-38185 updated cvss 7.0

cpio: integer overflow in ds_fgetstr() in dstring.c can lead to an out-of-bounds write via a crafted pattern file

  • Red Hat Enterprise Linux 6 cpio Red Hat Enterprise Linux 7 cpio
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux BaseOS (v. 8) cpio 2.12-11.el8
    fixed: vendor fix RHSA-2022:1991
  • Red Hat Enterprise Linux 9 cpio
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
17 mo ago

Exploit prediction

4.17% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/fangqyi/cpiopwn referenced PoC, tagged "exploit" by a source, unverified
  • lists.gnu.org https://lists.gnu.org/archive/html/bug-cpio/2021-08/msg00000.html referenced PoC, tagged "exploit" by a source, unverified
  • lists.gnu.org https://lists.gnu.org/archive/html/bug-cpio/2021-08/msg00002.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.