Link following in crun - CVE-2026-47766
Published: May 27, 2026
Vulnerability identifier: #VU132379
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-47766
CWE-ID: CWE-59
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Container Projects
Affected software:
crun
crun
Detailed vulnerability description
The vulnerability allows a local user to create device nodes and symlinks outside the container rootfs.
The vulnerability exists due to improper link resolution in create_missing_devs() in src/libcrun/linux.c when processing an OCI bundle whose rootfs/dev is a symlink and /dev is not mounted. A local user can supply a crafted bundle to create device nodes and symlinks outside the container rootfs.
A pre-existing file named ptmx at the symlink target can be replaced with a pts/ptmx symlink before crun returns failure.
How to mitigate CVE-2026-47766
Install security update from vendor's website.