CVE-2026-81578

Q: How do I fix CVE-2026-81578?

Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Q: Is CVE-2026-81578 being actively exploited?

Yes. CVE-2026-81578 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2026-09-14. Treat it as a priority whatever its CVSS score says.

Q: How severe is CVE-2026-81578?

CVE-2026-81578 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-81578 affect?

Published advisories record a fix for papercut mf (NVD), papercut ng (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

CRITICALCISA KEVEPSS 75th pctl

9.8

CVSS v3

NVD

Description

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.

CWE-305

How to fix

Remediation Available

papercut mfNVD

Affected:< 24.1.9Fixed in:24.1.9CVE-2026-81578derived from NVD

Affected:>= 26.0.2, < 26.0.4Fixed in:26.0.4CVE-2026-81578derived from NVD

Affected:>= 25.0.2, < 25.0.12Fixed in:25.0.12CVE-2026-81578derived from NVD

papercut ngNVD

Affected:< 24.1.9Fixed in:24.1.9CVE-2026-81578derived from NVD

Affected:>= 25.0.2, < 25.0.12Fixed in:25.0.12CVE-2026-81578derived from NVD

Affected:>= 26.0.2, < 26.0.4Fixed in:26.0.4CVE-2026-81578derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

1.62%probability of exploitation in 30 days

75thpercentile

Elevated risk: more likely to be exploited than 75% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Remediation due: 2026-09-14

References

Patch3

Related Vulnerabilities

Other CWE-305 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-31161	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-10923	High	8.8	85%	-	-
CVE-2023-28126	Medium	5.9	67%	-	-
CVE-2023-34124	Critical	9.8	50%	-	Fix
CVE-2025-32011	Critical	9.8	27%	-	-
CVE-2024-37085	Medium	6.8	27%	KEV + Ransom	Fix

Common questions

How do I fix CVE-2026-81578?

Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-81578 being actively exploited?

Yes. CVE-2026-81578 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2026-09-14. Treat it as a priority whatever its CVSS score says.

How severe is CVE-2026-81578?

CVE-2026-81578 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-81578 affect?

Published advisories record a fix for papercut mf (NVD), papercut ng (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2026-81578

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This vulnerability is actively exploited in the wild

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-14.