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NVD / CVE Program· CNA PaperCut

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

HighCVSS 8.8 · v4.0KEVWeaponized Fix available

Noroxi assessment

Priority: Now (action score 90/100)

  • CISA has confirmed exploitation in the wild (Aug 31, 2026). Remediation deadline for US federal agencies: Sep 14, 2026.
  • A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
  • Probability of exploitation in the next 30 days: 84.7% (FIRST EPSS); higher than 99.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: PaperCut PaperCut MF/NG 24.1.10, 25.0.13, 26.0.5.

Patch today or shut off access. Upgrade to PaperCut PaperCut MF/NG 24.1.10, 25.0.13, 26.0.5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

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.

Published
Aug 28, 2026
Updated
Sep 13, 2026
EPSS
84.7% · 99th percentile

Report tools

JSON

Action score

90

Now

Patch today or shut off access.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
25 / 30 · 84.7%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · PaperCut
8.8
NVD has not scored this yet; the score shown is the CNA’s.

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 score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Aug 31, 2026. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Sep 14, 2026.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-81578

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
papercutpapercut mf
papercutpapercut ng

Versions reported by the vendor

Affected version ranges reported by the assigning authority (PaperCut). Independent of NVD's CPE analysis and usually ahead of it.

  • PaperCut PaperCut MF/NG

    • before 24.1.10affected · semver
    • 25.0.0 and later · before 25.0.13affected · semver
    • 26.0.0 and later · before 26.0.5affected · semver
Affected versions · NVD (6)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • papercut papercut mfbefore 24.1.9
  • papercut papercut mf25.0.2 and later · before 25.0.12
  • papercut papercut mf26.0.2 and later · before 26.0.4
  • papercut papercut ngbefore 24.1.9
  • papercut papercut ng25.0.2 and later · before 25.0.12
  • papercut papercut ng26.0.2 and later · before 26.0.4

Same product

papercut: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-27350This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914).KEV
    99Now
  • CVE-2026-82078PaperCut MF/NG: Unsafe Dynamic Class Loading in Database ConnectorKEV
    86Now
  • CVE-2023-27351This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914).KEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-5115Mar 30, 2026 · Session hijacking in PaperCut NG/MF embedded application for Konica Minolta devices
    14Monitor
  • ← EarlierCVE-2026-6180May 5, 2026 · PaperCut MF: Card truncation on HP readers
    16Monitor
  • ← EarlierCVE-2026-6418May 5, 2026 · PaperCut NG/MF: Path Traversal in Shared Account Synchronization
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
PaperCut PaperCut MF/NG24.1.10Vendor (CNA)
PaperCut PaperCut MF/NG25.0.13Vendor (CNA)
PaperCut PaperCut MF/NG26.0.5Vendor (CNA)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Metasploit moduleexploit/multi/http/papercut_ng_external_user_lookup_rcePaperCut NG/MF Unauthenticated RCE (CVE-2026-81578 + CVE-2026-82078)exploit2026-08-27
Nuclei detection templateNuclei template CVE-2026-81578 —
Proof-of-concept repository on GitHubstars:42026-08-29
Proof-of-concept repository on GitHubstars:22026-08-29

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploit-2 d
  2. Published
  3. First PoCsame day
  4. CISA KEV+2 d
  5. TodayNov 13, 2026+77 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2026-6418115 days apartPaperCut NG/MF: Path Traversal in Shared Account Synchronization
    18Monitor

Not on record for this CVE: researcher credit · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (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/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records