CVE-2026-81578
PaperCut PaperCut MF/NG
Summary
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…
Published: 2026-08-28 · In KEV since: 2026-08-31
Analysis
🔴 Critical — actively exploited
Weakness: CWE-305.
How it's exploited: Exploitable over the network (internet-reachable), unauthenticated, no user interaction, and with low complexity.
⚠️ Critical combo: remote, unauthenticated and no interaction → trivial to automate.
Impact: Confidentiality partial · Integrity high · Availability partial.
Status: Active exploitation confirmed by CISA (KEV).
- Patch now: it is in CISA's actively-exploited catalog (KEV), with a deadline.
- Reduce exposure: keep it off the internet; firewall, VPN or network segmentation.
- Detect: turn this CVE into detection rules.
CVSS 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
The vector encodes how it's exploited (translated above, in the analysis). Break it down in the CVSS tool →
Sources: CISA KEV · EPSS · FIRST.org · NVD. Analysis derived from the CVSS vector and exploitation status (no AI). Informational; always verify against the vendor's official advisory.