CVE-2020-5291

CVE-2020-5291 describes a privilege escalation vulnerability in Bubblewrap (bwrap) versions prior to 0.4.1. When bwrap is installed in setuid mode and unprivileged user namespaces are supported by the kernel, an attacker can leverage the --userns2 option to maintain root privileges while being traceable, ultimately leading to root access. This primarily affects specific configurations of Debian, Arch (with linux-hardened), and CentOS (Flatpak COPR) where unprivileged user namespaces are enabled. The vulnerability carries a CVSS v3.1 score of 7.8 (High), indicating a local attack vector with low attack complexity and requiring low privileges, but resulting in high impact to confidentiality, integrity, and availability. The EPSS score is very low, suggesting a minimal likelihood of exploitation in the wild. There is no evidence of active exploitation, nor are there publicly available exploit modules in Metasploit, Nuclei, or ExploitDB. Community discussion and media coverage for this CVE are also minimal, indicating a low level of public attention.