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CVE-2026-18556

Unauthenticated administrative account takeover

Published: Aug 1, 2026Updated: Aug 5, 2026 Sources: CVE List NVDCWE-288

Description

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.

In plain language

AI Act now

CVE-2026-18556 is a way to bypass login and take over an admin account in N-able N-central; because it’s been exploited in the real world and is listed by CISA, a typical small business should treat it as urgent and patch or disable the system if you use it.

Executive summary

CVE-2026-18556 is an unauthenticated administrative account takeover in N-able N-central caused by an authentication-bypass weakness (CWE-288) that lets attackers impersonate an administrator over the network without prior credentials; CISA KEV confirms active real-world exploitation.

If affected, business impact
Full admin account takeoverManaged systems compromise riskSuspicious remote access enabled

What to do now

  1. Check whether your business uses N-able N-central and whether it’s reachable from the internet (or from any untrusted network).
  2. Confirm with your IT/vendor whether your N-central version is within the affected range (through 2026.1) and whether it has already been updated with the August 2, 2026 security fix.
  3. Apply N-able’s remediation guidance and install the security update referenced by N-able’s August 2, 2026 advisory.
  4. If mitigations/patching can’t be applied quickly, discontinue use of the product or restrict it so it’s not reachable from untrusted networks, per CISA guidance.
Patch / advisory Some work to apply

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None

Weaknesses

Affected Products

and 1 more affected products View all →

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:Aug 4, 2026
Remediation due:Aug 7, 2026

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.

Official Patch Available

References

15
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