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CVE-2026-81578

HIGH 8.8 KNOWN EXPLOITED PoC CATALOGUED DETECTION TEMPLATE ALL-YEARS

Published 2026-08-28 · Last modified 2026-09-13 · PaperCut · NVD: Analyzed

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.

ACTIVELY EXPLOITED

Confirmed exploited in the wild — in CISA KEV since 2026-08-31. Patch or mitigate now.

Exploitation likelihood

83.7%chance of exploitation in 30 days · 100th percentile

● In CISA KEV (2026-08-31)● Catalogued PoC◆ SSVC: exploitation active, automatable yes

Impact if exploited

8.8CVSS 4.0 · HIGH · CNA

  • ConfidentialityLow
  • IntegrityHigh
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable
  • ✓Requirements: No special attack requirements

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

Public PoC or exploit resources are catalogued below.

Listed by the named source; Vulnpedia has not tested these resources.

PoC data: JSON

Detection templates

Detection checks are listed separately from PoCs.

Resource commands

nuclei -id CVE-2026-81578 -u https://TARGETDetection template — review its checks and affected versions before use.
curl -s https://vulnpedia.com/cve/CVE-2026-81578/poc.jsonMachine-readable PoC index for this CVE (for automation).

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Papercut

Products Papercut Mf/Ng Papercut Mf Papercut Ng

Weakness (CWE)

  • CWE-305: Authentication bypass by primary weakness

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

References and research data (JSON)

Unverified PoC candidates

Catalogue matches for further research. These repositories have not been validated as working exploits.

2 candidates

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

Known Affected Software Configurations

VendorProductVersion range
PapercutPapercut Mf< 24.1.9
PapercutPapercut Mf≥ 25.0.2 and < 25.0.12
PapercutPapercut Mf≥ 26.0.2 and < 26.0.4
PapercutPapercut Ng< 24.1.9
PapercutPapercut Ng≥ 25.0.2 and < 25.0.12
PapercutPapercut Ng≥ 26.0.2 and < 26.0.4

All CVSS metrics

  • HIGH 8.8 v4.0 · CNA Primary
    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
  • HIGH 8.8 v4.0 · NVD Secondary
    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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
  • CRITICAL 9.8 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Exploit-tagged references (not proof of a PoC)

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS