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CVE-2026-18556 CISA KEV — actively exploited

N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability

N-able — N-central

Authentication bypass using an alternate path or channel vulnerability in N-able N-central allows Authentication Bypass. This issue affects N-central: through 2026.1.

CVSS scoreHigh

7.4

EPSS — exploitation probabilityMedium

40.2%

Vector breakdown

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

Published
Aug 1, 2026
Modified
Oct 23, 2026
Added to KEV
Aug 4, 2026
Federal patch due
Aug 7, 2026

CISA required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Weakness classification

Proof-of-concept & exploitation references

Public repositories whose name or description references CVE-2026-18556, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.

No public GitHub repositories referencing CVE-2026-18556 were found at last check. Absence here is not proof no exploit exists — see the references below for vendor advisories and write-ups.

References

Frequently asked questions

What is CVE-2026-18556?

Authentication bypass using an alternate path or channel vulnerability in N-able N-central allows Authentication Bypass. This issue affects N-central: through 2026.1.

How severe is CVE-2026-18556?

CVE-2026-18556 has a CVSS base score of 7.4 out of 10 (CVSS 3.1).

Is CVE-2026-18556 actively exploited in the wild?

Yes. CVE-2026-18556 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Aug 4, 2026, meaning CISA has confirmed evidence of active exploitation.

What is the EPSS score for CVE-2026-18556?

40.2% - meaning FIRST.org's EPSS model estimates a 40.2% probability this vulnerability will be exploited in the wild within 30 days (99% percentile among all scored CVEs).

What type of vulnerability is CVE-2026-18556?

CVE-2026-18556 is classified under CWE-288 (CWE-288 Authentication bypass using an alternate path or channel).

Cross-checked against

Impactr finds and proves whether CVE-2026-18556 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.