Live Exposure Defense: From CVE to Confirmed Exposure in 12 Hours – See more

Back
New CVE Detected

CVE-2026-81578 – Unauthenticated Admin Access Bypass (RCE Chain) – PaperCut NG/MF before 24.1.10, 25

Be the first to know when new zero-days emerge:

Subscribe to Email Alerts
Subscribe to RSS Feed

Summary

CVE-2026-81578 is an improper access control vulnerability (CWE-305) in the web management interface of PaperCut NG and PaperCut MF that allows unauthenticated remote attackers to trigger backend administrative functions and modify system configuration without authentication. The flaw has a CVSS score of 8.8 and is being actively exploited in the wild, reportedly chained with a second PaperCut vulnerability (CVE-2026-82078) to achieve remote code execution on affected Application Servers.

Technical details

  • Root cause: Backend administrative actions in the PaperCut Application Server’s web management interface execute before the access-control/authentication validation checks complete, allowing the checks to be bypassed entirely.
  • Trigger conditions: An attacker sends specially crafted, unauthenticated HTTP requests directly to administrative endpoints of the PaperCut Application Server’s web interface.
  • Attack vector: Network-based; no authentication or user interaction required, and the requests can originate from any internet-facing client that can reach the server.
  • Impact: Unauthenticated modification of system configuration; when chained with CVE-2026-82078 (unsafe dynamic class loading in the database connection utilities), this can escalate to arbitrary code execution on the underlying server.

Affected software

  • PaperCut NG and PaperCut MF versions prior to 24.1.10
  • PaperCut NG and PaperCut MF versions prior to 25.0.13
  • PaperCut NG and PaperCut MF versions prior to 26.0.5

Severity

  • CVSS v4.0 Base Score: 8.8 (High)
  • Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N

Mitigation and recommended actions

  • Immediate: Upgrade PaperCut NG/MF to version 24.1.10, 25.0.13, or 26.0.5 (or later). PaperCut has issued an updated "Release 2" emergency patch with additional hardening beyond the initial emergency fix — install Release 2 even if the original emergency patch was already applied.
  • If patching is not immediately possible: Restrict network access to the PaperCut Application Server’s web interface to trusted/internal IP addresses only using firewall rules or network access controls, preventing any untrusted internet address from reaching the server.
  • Monitor for indicators of compromise noted by the vendor, including unexpected activity from the pc-app.exe process and missing, truncated, or deleted PaperCut server.log files.

References

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report

How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
Close

Subscribe to Threat Center RSS

Copy/paste the link below into your preferred RSS reader or follow these instructions to subscribe to Slack alerts.

Open RSS feedSlack setup instructions

Close

Get Real-Time CVE Alerts to Your Email

Be the first to know when new zero-days emerge