CVE-2026-66486: gnu cpio Improper Encoding or Escaping of Output

Vulnerability summary

CVE-2026-66486 is a medium (CVSS 4.6) Improper Encoding or Escaping of Output vulnerability in gnu cpio. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.5% of scored vulnerabilities.

Timeline

1. 10-08-2026
   PublishedVulnerability first disclosed.
2. 10-08-2026
   Last modifiedVulnerability information updated.

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

• CWE-116Improper Encoding or Escaping of OutputThe 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.