Jan 2, 2026·5 min read·1 visit
Buildah and Docker Engine (Moby) were initializing containers with a fully populated 'Inheritable' capability set. This violated the principle of least privilege, allowing processes within the container to easily elevate their privileges to the container's maximum bounding set simply by executing binaries with file capabilities set. It's a classic case of "default insecure" configuration.
A deep dive into a subtle but significant flaw in how Buildah and Docker Engine initialized Linux process capabilities. By misconfiguring the Inheritable set, these runtimes allowed unintended privilege escalation within containers, turning the complex mathematics of Linux permissions against the security model.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N| Product | Affected Versions | Fixed Version |
|---|---|---|
Buildah Containers | <= 1.24.0 | 1.25.0 |
Moby (Docker) Moby Project | < 20.10.9 | 20.10.9 |
| Attribute | Detail |
|---|---|
| CWE ID | CWE-276 |
| Attack Vector | Local (Container) |
| CVSS | 6.8 (Medium) |
| Impact | Privilege Escalation (Intra-Container) |
| Exploit Status | PoC Available |
| Vulnerable Component | OCI Runtime Spec Generation |
Incorrect Default Permissions