CVE-2025-8766
Description
A container privilege escalation flaw was found in certain Multi-Cloud Object Gateway Core images. This issue stems from the /etc/passwd file being created with group-writable permissions during build time. In certain conditions, an attacker who can execute commands within an affected container, even as a non-root user, can leverage their membership in the root group to modify the /etc/passwd file. This could allow the attacker to add a new user with any arbitrary UID, including UID 0, leading to full root privileges within the container
Statement
Red Hat Product Security has rated this vulnerability as moderate severity for affected products which run on OpenShift. The vulnerability allows for potential privilege escalation within a container, but OpenShift's default, multi-layered security posture effectively mitigates this risk.
The primary controls include the default Security Context Constraints (SCC), which severely limit a container's permissions from the start, and SELinux, which enforces mandatory access control to ensure strict isolation. While other container runtime environments may have different controls available and require case-by-case analysis, OpenShift's built-in defenses are designed to prevent this type of attack.
Out of Box RHEL configuration isolates a single process inside a container. Unless multiple processes are packaged inside a single container, that defeats the principle behind containerization, this bug can not be used to meaningfully escalate privileges.
Also, RHEL, and any common linux distributions do NOT add any additional users to the root group. The presence of the root group is strictly due to conformance with POSIX permission management requirements and can be considered to be an artifact of filesystem permission limitations.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.4 | 6.4 | 6.4 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | High | High | High |
| Privileges Required | High | High | High |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity
Technical Impact: Read Application Data; Modify Application Data
Acknowledgements
Red Hat would like to thank Antony Di Scala and Michael Whale for reporting this issue.
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