CVE-2026-47128

EUVD-2026-46116 · Published May 28, 2026

nono: Sandbox escape on Linux via D-Bus: systemd-run --user

Summary

The nono Landlock/seccomp policies allow access to local Unix domain sockets (concrete and abstract). This allows an easy sandbox escape by talking to the per-user systemd dbus socket.

Threat scenario: Running Aider, Claude Code, OpenCode or similar tools with "allow bash" policy so that it can invoke arbitrary host tools like make, gcc, etc. to write code.

Reproducer

Here, instead of running a tool like opencode or claude one can just invoke systemd-run, but this is something an agent could be tricked into doing:

$ cd ~/src/myproject
$ nono run -s --allow-cwd --profile claude-code -- \
      systemd-run --user -q --wait --collect \
      /bin/sh -c "echo oops > ~/Documents/escaped.txt"
$ cat /var/home/test/Documents/escaped.txt
oops
$

Impact

Complete sandbox escape. The unsandboxed sibling process can write anywhere the user can write, spawn arbitrary processes with network access, etc.

Maintainer Context

This issue allows a process running inside the sandbox to escape confinement by interacting with local user-scoped IPC mechanisms and regain the authority already held by the invoking user or service account.

The issue impacts the sandbox’s confinement and blast-radius reduction guarantees for agents and sandboxed tooling. However, exploitation does not provide privilege escalation, cross-user access, or host compromise beyond the permissions already available to the launcher outside the sandbox.

This issue affects the CLI policy layer and bundled sandbox profiles. The underlying core library nono does not ship with policy definitions or agent-facing confinement profiles by default, nor do the language SDKs.

This is considered a serious issue because an AI agent or untrusted command stream operating within the sandbox could abuse the bypass to perform unauthorized or destructive actions using the delegated authority of the launching user.

The root cause was incomplete mediation of local Unix domain socket access within affected sandbox policies. Support for restricting this behavior has since been added and the fix is available in the repository pending release.

CVSS rationale: exploitation requires execution within a locally launched sandboxed process using the authority already delegated by the invoking user or service account (AV:L/PR:L). The issue allows reliable bypass of sandbox confinement and policy guarantees, resulting in high integrity impact (I:H) and limited availability impact (A:L) through destructive actions within the launcher’s existing permissions. However, the issue does not provide privilege escalation, cross-user access, or a change in security scope (S:U).

Technologies

Nono-Cli Nono-Cli

Weaknesses

CWE-863

CVSS scores

v3.16.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

MITRE ATT&CK

Inferred

Where this vulnerability fits in an attack

ReconImpact

Privilege Escalation

T1068Exploitation for Privilege Escalation

References

Potentially impacted assets

See if this affects your attack surface

Latest trending attack

Criticalyesterday

Google Brotli decoder - Remote Code Execution via compressed requests (Exploitation Check)

This control is the second step of the Patrowl response to CVE-2026-111497 (Node2Shell). It complements the first control of 22 October 2026, which focused on the Node.js runtime, and does not replace it. Why a second control CVE-2026-111497 is an out-of-bounds write in the Google Brotli decoder, the library that decompresses Brotli ("br") data. It was first published as a Node.js vulnerability, because Node.js bundles this decoder. Later publications showed that the flaw is in the library itself. Every product that embeds an affected version of the decoder is concerned, whatever its language or vendor. A public proof of concept demonstrates code execution. Any server that decompresses request bodies sent with "Content-Encoding: br" exposes the decoder to unauthenticated attackers. Known cases include Express 5 and NestJS 11 on Node.js, Koa and Fastify setups, Bun, Envoy and Istio with request decompression enabled, and any application or reverse proxy that decodes Brotli request bodies with an affected library. The flaw also works in the other direction. A malicious server can compromise an unpatched client that decodes a Brotli response, for example Node.js fetch(), Python clients (requests, httpx, aiohttp, Scrapy) with the Brotli or brotlicffi package, or libcurl builds with Brotli support. What this control checks Patrowl sends small, valid Brotli-compressed requests to each asset and observes whether the server decodes them. The check does not depend on the technology: it detects the behaviour, whatever the stack behind it. These requests are what any legitimate client could send. They never reach the vulnerable code path and cannot affect the availability of the service. How to read the result Potentially impacted means the asset decodes Brotli request bodies: the attack surface is exposed. It does not confirm that the asset is vulnerable. The version of the Brotli decoder in use is not visible from the outside. This check covers applications that parse request bodies on their root path. A Not impacted result does not rule out exposure on other routes, nor on the client side. Checking the versions on the servers remains the only exhaustive verification. Affected and fixed versions Google Brotli 1.0.3 to 1.2.0 are affected, fixed in 1.0.10, 1.1.1 and 1.2.1. Fixed releases of the main products embedding it: Node.js 22.23.4, 24.22.1 and 26.12.1 (end-of-life lines 20.x and older and 25.x receive no fix), Bun 1.4.4, Envoy 1.37.8, 1.38.6, 1.39.3 and 1.40.0, Istio 1.29.9, 1.30.6 and 1.31.2, Python Brotli 1.2.1 and brotlicffi 1.2.1.0. Products that link against the system library depend on the Brotli package of the Linux distribution. Recommendations Update every component that embeds the Brotli decoder (only real fix). Start with the assets flagged by this control. Restart the processes after the update. Rebuild containers, single-executable applications and appliances that bundle an affected runtime or library. Reduce the exposure until the update is deployed. Reject requests with "Content-Encoding: br" at the reverse proxy, load balancer or WAF, case-insensitively and including lists such as "gzip, br". On Envoy and Istio, disable request decompression for Brotli. Review outbound calls. List the features that fetch content from servers you do not control, and patch the services that host them first.