CVE-2021-26937: encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a denial of service (invalid write...

Security readout for executives and security teams

CVE-2021-26937 is a GNU Screen crash issue in versions through 4.8.0. A maliciously formed UTF-8 character sequence can trigger invalid memory writes, causing denial of service and possibly other unspecified impact. The sources do not provide a CVSS score or evidence of active exploitation. Systems running GNU Screen through 4.8.0 are the primary concern, including Linux/Unix servers and products that bundle Screen. Practical exposure depends on whether untrusted or remote-controlled terminal content can be processed inside Screen sessions. Handle in normal patch cycles, faster for shared administration servers or appliances where Screen processes untrusted output. There is no sourced evidence of active exploitation, but a crash in administrator tooling can disrupt operations. Mitigation focus: Inventory systems for GNU Screen versions through 4.8.0.; Apply vendor security updates for Screen from your operating system or product vendor.; Prioritize multi-user systems and hosts processing untrusted terminal output..

Prepared

Jun 3, 2026, 03:23 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.