VNCAuthProxy authentication bypass vulnerability

Exploitation

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

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2022-36436: 2.07% estimated exploitation activity in the next 30 days; percentile 81.46 (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.

OSU Open Source Lab VNCAuthProxy through 1.1.1 is affected by an vncap/vnc/protocol.py VNCServerAuthenticator authentication-bypass vulnerability that could allow a malicious actor to gain unauthorized access to a VNC session or to disconnect a legitimate user from a VNC session. A remote attacker with network access to the proxy server could leverage this vulnerability to connect to VNC servers protected by the proxy server without providing any authentication credentials. Exploitation of this issue requires that the proxy server is currently accepting connections for the target VNC server.

Published by the source

16 Sep 2022, 17:11 UTC

Last modified by the source

18 Nov 2024, 23:23 UTC

Source last checked

26 Oct 2026, 13:16 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-237r-mx84-7x8c

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-237r-mx84-7x8c

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# Patch Next advisory brief: CVE-2022-36436

Advisory: VNCAuthProxy authentication bypass vulnerability
IDs: CVE-2022-36436, GHSA-237r-mx84-7x8c
Record: https://patchnext.com/advisories/cve-2022-36436 (revision 3, source checked 26 Oct 2026, 13:16 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: vncauthproxy 1.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI vncauthproxy: affected < 1.2.0; fixed in 1.2.0

## Suggested inspection (read-only)
- `python -m pip show vncauthproxy`: 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 vncauthproxy.
- 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-237r-mx84-7x8c (OSV record GHSA-237r-mx84-7x8c lists affected ranges: PyPI vncauthproxy >=0 <1.2.0 (fixed))
- Verified: https://github.com/advisories/GHSA-237r-mx84-7x8c (GitHub-reviewed advisory GHSA-237r-mx84-7x8c lists affected ranges: PyPI vncauthproxy >=0 <1.2.0)

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