CVE-2026-66486
Received Received - Intake

Improper Output Encoding in GNU cpio Archive Listing

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: CERT.PL

Description
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

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-66486
EUVD
EUVD-2026-55244

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
gnu cpio to 2.11.0 (inc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-116 The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

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Executive Summary

GNU cpio has a flaw where archive member names are printed without proper encoding or escaping during listing. Attackers can embed newline characters or ANSI escape sequences in filenames to manipulate output or inject terminal control sequences when using 'cpio -it'.

Detection Guidance

To detect this vulnerability, inspect cpio archives for member names containing newline characters or ANSI escape sequences. Use commands like: find /path/to/archives -name '*.cpio' -exec cpio -it < {} \; 2>&1 | grep -P '[\n\x1b]' to check for suspicious output.

Impact Analysis

This vulnerability could allow attackers to forge listing entries or execute terminal control sequences by tricking users into viewing a malicious cpio archive. This might lead to misinformation or unintended terminal behavior.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA. It primarily impacts terminal output integrity by allowing forged listing entries or terminal control sequence injection through crafted archive member names. No evidence suggests it impacts data confidentiality, integrity, or availability in a way that would violate these standards.

Mitigation Strategies

Update GNU cpio to a version containing the fix in commit 2ff9600c9ef32e88759843cdbde74c8db5ae9b30. Avoid listing archives from untrusted sources until patched.

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