# CVE-2026-82077 — PaperCut NG/MF

> As of 2026-09-25, CVE-2026-82077 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in PaperCut NG/MF, CVSS v4.0 7.3, EPSS 0.7% (53.1th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-82077, most recently “PaperCut NG/MF Chained Zero-Day RCE (CVE-2026-82078 & CVE-2026-81578) Under Active Exploitation”.

**Last updated:** 2026-09-25

## What is CVE-2026-82077?

An improper limitation of a pathname to a restricted directory (path traversal) vulnerability in the Scan-to-Fax component of PaperCut NG and PaperCut MF allows an authenticated administrator to execute arbitrary commands on the underlying host via crafted fax provider settings.

The record classifies CVE-2026-82077 under weakness classes [CWE-22](https://intel.threadlinqs.com/cwe/CWE-22), [CWE-78](https://intel.threadlinqs.com/cwe/CWE-78). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 20 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 7.3 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **EPSS (FIRST):** 0.7% probability of exploitation in the next 30 days, higher than 53.1% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 5.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-24, last modified 2026-09-25

## Is CVE-2026-82077 being exploited?

It currently carries a trending score of 44 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [PaperCut](https://intel.threadlinqs.com/vendors/papercut): NG/MF

## How to fix CVE-2026-82077

No vendor patch reference has been recorded for CVE-2026-82077 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-82077

1 tracked threat in the Threadlinqs corpus references CVE-2026-82077, either in the campaign’s CVE list or as an indicator on the campaign record.

- [PaperCut NG/MF Chained Zero-Day RCE (CVE-2026-82078 & CVE-2026-81578) Under Active Exploitation](https://intel.threadlinqs.com/threat/TL-2026-2184) — CRITICAL · 2026-08-28

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-10.

**Other references**

- [papercut.com](https://www.papercut.com/kb/Main/security-bulletin-sep-2026/)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-82077
Full detection coverage and IOCs for threats exploiting CVE-2026-82077 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp