CVE-2026-18577: N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run N-able N-central. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-08-03, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-08-06; treat that as the outer limit, not the target.
• EPSS 14.6%, percentile 97: FIRST’s model estimates a 14.6% chance of exploitation activity in the next 30 days, higher than 97% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Editorial verdict: Act now. N-able N-central: Exploited Auth Bypass and Pre-Auth RCE — Any self-hosted N-central server below 2026.3.1.14 should be treated as exposed and patched today, and any server that was patched late needs a compromise review, because one stolen RMM console reaches every managed endpoint.

What it is

An incomplete patch for CVE-2026-18556 allows for authentication bypass and account takeover in N-central Versions through 2026.3.1

CISA’s summary

N-able N-central contains an authentication bypass using an alternate path or channel allows for authentication bypass and account takeover in N-central. This vulnerability is the result of an incomplete patch for CVE-2026-18556.

Weakness type: CWE-288.

Product: N-able N-central · Assigned by: N-able · Published: 2026-08-02

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: high (needs special conditions)
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2026-08-03; federal due date 2026-08-06. Known ransomware use: Unknown.
• 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.
• CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 14.62% probability of exploitation activity in the next 30 days; percentile 97.

Timeline

• 2026-08-01 — erroneo.us brief: N-able N-central: Exploited Auth Bypass and Pre-Auth RCE
• 2026-08-02 — CVE record published by N-able
• 2026-08-03 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2026-08-04 — CVE record last updated
• 2026-08-06 — CISA remediation deadline for US federal agencies

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. n-able.com n-able.com
2. Listed in CISA KEV notes (documentation.n-able.com) documentation.n-able.com
3. Listed in CISA KEV notes (status.n-able.com) status.n-able.com

Vulnerability records

1. CVE.org record CVE-2026-18577 cve.org
2. NVD entry CVE-2026-18577 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov
2. Listed in CISA KEV notes (cisa.gov) cisa.gov
3. Listed in CISA KEV notes (cisa.gov) cisa.gov

Other references from the CVE record and advisory

1. cve.org cve.org

All exploited N-able vulnerabilities · Today’s Security Digest