CVE-2026-84042
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk1th percentile - higher than 1% of all known CVEs
Summary
In crun, when built with libkrun and a container is started rootful with passt networking (krun.use_passt), crun can execute attacker-controlled payload from the container image with host root privileges. This is a regression in crun 1.29 and affects crun >= 1.29.
Risk Assessment
An attacker able to supply a container image can gain root privileges on the host, leading to full compromise of the host system.
Recommendation
Update crun to a version that fixes the regression, or avoid rootful configurations with passt networking until a patch is available.
Other vulnerabilities in crun
See all- CVE-2026-47766Medium
crun before version 1.28 contains a vulnerability in the default device setup that opens the container rootfs `/dev` directory without `O_NOFOLLOW`. If an OCI bundle contains `rootfs/dev` as a symlink and the bundle configuration does not mount `/dev`, crun follows that symlink and creates default device nodes and stdio symlinks at the symlink target outside the container rootfs. This can lead to overwriting existing files, such as ptmx.
- CVE-2026-88265Medium
A flaw was found in crun. After pivot_root, reopening /dev/null for stdio can follow a symlink and attach a host file to container stdio, then change that file's ownership. Affected versions are crun 1.29.1 and earlier. Default configurations that mount a fresh /dev are not exposed. No fixed release is available yet.
- CVE-2026-88264Medium
A flaw was found in crun. When the container configuration does not give /dev a dedicated mount, terminal setup can redirect /dev/console onto an attacker-controlled path, including via the read-only-rootfs bind-mount fallback. Affected versions are crun 1.29.1 and earlier. Default configurations that mount a fresh /dev are not exposed. No fixed release is available yet.
Original NVD description (English source)
A flaw was found in crun. When crun is built with libkrun and a container is started rootful with passt networking (krun.use_passt), crun can execute attacker-controlled payload from the container image with host root privileges. The issue is a regression in crun 1.29. It affects crun >= 1.29