Dynamic modification of RPyC service due to missing security check

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

EPSS

• CVE-2019-16328: 13.05% estimated exploitation activity in the next 30 days; percentile 96.35 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Version 4.1.0 of RPyC has a vulnerability that affects custom RPyC services making it susceptible to authenticated remote attacks.

Patches Git commits between September 2018 and October 2019 and version 4.1.0 are vulnerable. Use a version of RPyC that is not affected.

Workarounds The commit `d818ecc83a92548994db75a0e9c419c7bce680d6` could be used as a patch to add the missing access check.

References CVE-2019-16328 RPyC Security Documentation

For more information If you have any questions or comments about this advisory: * Open an issue using GitHub

Proof of Concept ``` import logging import rpyc import tempfile from subprocess import Popen, PIPE import unittest PORT = 18861 SERVER_SCRIPT = f"""#!/usr/bin/env python import rpyc from rpyc.utils.server import ThreadedServer,…

Published by the source

17 Feb 2021, 19:50 UTC

Last modified by the source

8 Nov 2023, 04:01 UTC

Source last checked

24 Oct 2026, 04:13 UTC

1. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-pj4g-4488-wmxm

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# Patch Next advisory brief: CVE-2019-16328

Advisory: Dynamic modification of RPyC service due to missing security check
IDs: CVE-2019-16328, GHSA-pj4g-4488-wmxm
Record: https://patchnext.com/advisories/cve-2019-16328 (revision 1, source checked 24 Oct 2026, 04:13 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: rpyc 4.1.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI rpyc: affected >= 4.1.0, < 4.1.1; fixed in 4.1.1

## Suggested inspection (read-only)
- `python -m pip show rpyc`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on rpyc.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-pj4g-4488-wmxm (OSV record GHSA-pj4g-4488-wmxm lists affected ranges: PyPI rpyc >=4.1.0 <4.1.1 (fixed))

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