# CVE-2026-81578: PaperCut MF/NG - Authentication Bypass

> Live exploitation tracking for CVE-2026-81578 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2026-81578

## Key facts

- **Exploitation phase:** Limited Exploitation. The vulnerability is known but shows very limited attacker interest or exploitation activity.
- **CVSS score:** 8.8
- **Public exploit available:** Yes
- **Affected products:** PaperCut MF/NG
- **Weaknesses:** CWE-305 (Authentication Bypass by Primary Weakness)
- **Tags:** enterprise_software, management_panel

## Description

An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the  completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.

## CrowdSec analysis

[CVE-2026-81578](https://euvd.enisa.europa.eu/vulnerability/CVE-2026-81578) is a high-severity improper access control vulnerability in the PaperCut MF/NG web management interface. Under specific conditions, unauthenticated remote attackers can bypass access validation and invoke administrative backend actions, potentially modifying system configurations and disrupting or compromising the managed printing environment.

CrowdSec has been tracking this vulnerability and its exploits since 17th of September 2026.

CrowdSec has not observed any significant exploitation activity targeting CVE-2026-81578 across its network. As a result, no community-driven trend analysis is available for this vulnerability at this time.

Attackers target the PaperCut web interface at `/app`, using Tapestry service requests such as `/app?service=page/Error` and `/app?service=direct/<random>/Home/ConfigEditor/quickFindForm`. The exploit abuses a complex-direct request to invoke the privileged `ConfigEditor` form listener without authentication, typically submitting parameters such as `sp`, `Form0`, `$TextField`, and `doQuickFind`.

## Timeline

- 2026-08-28: CVE Published. CVE-2026-81578 is published to NVD.
- 2026-08-31: CISA KEV. CVE-2026-81578 is added to the Known Exploited Vulnerabilities catalog by CISA.
- 2026-09-14: CISA Remediation Deadline. Expiration of the CISA remediation deadline as described in [BOD 22-01](https://www.cisa.gov/news-events/directives/bod-22-01-reducing-significant-risk-known-exploited-vulnerabilities).
- 2026-09-17: Rule Released. CrowdSec releases a rule to detect CVE-2026-81578 exploitation attempts against the CrowdSec Network.
- 2026-09-28: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2026-81578 for the first time.

## References

- https://github.com/rapid7/metasploit-framework/pull/21842
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81578
- https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-81578.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2026-81578) follows observed exploitation activity for CVE-2026-81578. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.