CVE-2021-27135: Debian Linux

Critical severity, CVSS 9.8. EPSS: 7.8% chance of exploitation in the next 30 days.

xterm before Patch #366 allows remote attackers to execute arbitrary code or cause a denial of service (segmentation fault) via a crafted UTF-8 combining character sequence.

Affected products

• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 33 only
• Invisible-Island Xterm: before 366 (fixed in 366)

Published 2021-02-10. Last modified 2026-06-17.