CVE-2026-34040 — Docker/Moby AuthZ Plugin Bypass (Lab PoC)

KO: 这是通过超过 1MB 的请求体绕过 Docker(Moby) 授权(AuthZ) 插件的漏洞的实操复现项目。 EN: A lab reproduction of a vulnerability that bypasses Docker (Moby) authorization (AuthZ) plugins using an oversized (>1MB) request body.

Vulnerability facts / 漏洞事实

KO: 官方 CVSS 向量是 AV:L(本地)。即评估标准是具有本地 Docker API 访问权限(通常是 /var/run/docker.sock)的低权限用户。这个 PoC 也只使用本地 UNIX socket。 EN: The official CVSS vector is AV:L (Local). The rated scenario is a low-privileged user with local Docker API access (typically /var/run/docker.sock). This PoC uses the local UNIX socket only.

What this demonstrates / 这展示了什么

KO:

1. 正常大小的特权容器创建请求会被 AuthZ 插件阻止 (HTTP 403)。
2. 包含超过 1MB padding 的相同请求会绕过 AuthZ 检查。
3. 被绕过的请求到达 Docker Daemon 处理阶段，创建特权容器。
4. 通过 privileged + 主机 bind mount 组合，可以演示主机文件读取和主机命令执行。

EN:

1. A normal-sized privileged container-create request is blocked by the AuthZ plugin (HTTP 403).
2. The same request padded beyond 1MB bypasses the AuthZ check.
3. The bypassed request reaches the Docker daemon and creates a privileged container.
4. With privileged + host bind mount, host file read and host command execution can be demonstrated.

KO: 这个 CVE 本身不会直接读取 /etc/shadow 或执行 RCE。漏洞的本质是绕过 AuthZ 应阻止的 Docker API 请求；后续步骤(文件读取、chroot、命令执行)是利用 Docker/Linux 正常功能的影响演示。 EN: The CVE itself does not read /etc/shadow or perform RCE directly. The vulnerability is the bypass of a Docker API request that AuthZ should block; the later steps (file read, chroot, command execution) are impact demos that abuse normal Docker/Linux features.

Repository structure / 仓库结构

.
├── README.md
├── poc.py                  # Working PoC (local UNIX socket only)
├── requirements.txt        # Python standard library only
├── LICENSE
├── lab/
│   ├── authz.rego          # OPA policy: blocks privileged + host-root bind
│   └── daemon.json         # Registers the AuthZ plugin
└── docs/
    ├── concepts.md         # 개념 / Concepts
    ├── lab-setup.md        # 환경 구성 / Lab setup
    ├── how-it-works.md     # 동작 원리 / How it works (source-level)
    ├── usage.md            # 사용법 / Usage
    ├── troubleshooting.md  # 문제 해결 / Troubleshooting
    └── references.md       # 참고 / References

Prerequisites / 前提条件

KO: 要让这个 PoC 有意义地运行，需要满足以下所有条件。 EN: All of the following are required for this PoC to be meaningful.

Quick start / 快速开始

# 1) Pull the image used by the PoC
sudo docker pull alpine

# 2) Run the non-destructive bypass check
sudo python3 poc.py --mode check

Expected on a vulnerable target / 易受攻击目标上的预期结果:

small request     -> HTTP 403   (AuthZ blocks)
oversized request -> HTTP 201 or HTTP 404   (AuthZ bypassed; daemon processed it)

KO: 404 No such image 也是绕过的证据。这意味着请求没有被 AuthZ 阻止(403)，而是到达了 Docker Daemon 的镜像检查阶段。在演示/展示时，请提前 pull alpine 以避免混淆。 EN: A 404 No such image is still evidence of bypass — the request passed AuthZ (not 403) and reached the daemon's image lookup. Pull alpine beforehand to avoid confusion in a demo.

完整用法参见 docs/usage.md。 / See docs/usage.md for full usage.

Lab-only warning / 仅限实验警告

KO: 请仅在自己拥有或明确获准测试的隔离实验环境中使用。不要针对远程 Docker API、第三方服务器、生产环境或暴露在互联网上的 Docker endpoint 运行。影响演示模式(rce-proof、host-command、reverse-shell-local)需要显式确认标志才能运行。 EN: Use only in an isolated lab you own or are explicitly authorized to test. Do not run against remote Docker APIs, third-party servers, production, or internet-exposed Docker endpoints. The impact-demo modes (rce-proof, host-command, reverse-shell-local) require an explicit confirmation flag.

References / 参考资料

See docs/references.md. / docs/references.md 参见。