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NVD / CVE Program· CNA CERT-PL

CVE-2026-66486: Improper Output Encoding in GNU cpio

MediumCVSS 4.6 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 18/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: azl3 cpio 2.14-2 on Azure Linux 3.0 2.14-2.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to azl3 cpio 2.14-2 on Azure Linux 3.0 2.14-2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

GNU cpio is vulnerable to improper encoding or escaping of output in its archive member listing functionality. When listing archive members via cpio -it, member names are printed directly to output without quoting or escaping. An attacker can craft a cpio archive containing member names with embedded newline characters or ANSI escape sequences, causing forged listing entries or terminal control sequence injection when the listing is displayed. This issue has been fixed in commit 2ff9600c9ef32e88759843cdbde74c8db5ae9b30

Published
Aug 10, 2026
Updated
Oct 24, 2026
EPSS
0.1% · 8th percentile

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · CERT-PL
4.6
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-66486

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (CERT-PL). Independent of NVD's CPE analysis and usually ahead of it.

  • GNU cpio

    • up to and including 2.15affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12cpiofrom 0—
openSUSE:Leap 16.0cpiobefore 2.15-160000.3.12.15-160000.3.1
openSUSE:Tumbleweedcpiobefore 2.15-8.12.15-8.1
SUSE:Linux Enterprise Micro 5.3cpiobefore 2.13-150400.3.10.12.13-150400.3.10.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5cpiobefore 2.11-36.25.12.11-36.25.1
SUSE:Linux Micro 6.0cpiobefore 2.15-2.12.15-2.1
SUSE:Linux Micro 6.1cpiobefore 2.15-slfo.1.1_3.12.15-slfo.1.1_3.1
SUSE:Linux Micro 6.2cpiobefore 2.15-160000.3.12.15-160000.3.1

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-38185GNU cpio through 2.13 allows attackers to execute arbitrary code via a crafted pattern file, because of a dstring.c ds_fgetstr integer…
    32Monitor
  • CVE-2019-14866In all versions of cpio before 2.13 does not properly validate input files when generating TAR archives.
    29Monitor
  • CVE-2010-4226cpio, as used in build 2007.05.10, 2010.07.28, and possibly other versions, allows remote attackers to overwrite arbitrary files via a…
    29Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2023-7207Feb 28, 2024 · Debian's cpio contains a path traversal vulnerability.
    19Monitor
  • ← EarlierCVE-2026-66484Aug 10, 2026 · Path Traversal in GNU cpio
    18Monitor
  • ← EarlierCVE-2026-66485Aug 10, 2026 · Uncontrolled Memory Allocation in GNU cpio
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 cpio 2.14-2 on Azure Linux 3.02.14-2Microsoft (MSRC)
opensuse:cpio2.15-8.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:cpio2.15-slfo.1.1_3.1 · SUSE:Linux Micro 6.1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: patch commit or PR link · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-116 · Improper Encoding or Escaping of Output

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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