How severe is CVE-2026-18556?

No CVSS score has been assigned to CVE-2026-18556 yet. Review the advisory details and affected package list to assess your exposure.

Which products are affected by CVE-2026-18556?

CVE-2026-18556 affects the following products: N-able N-central.

How do I patch CVE-2026-18556?

No patch has shipped for CVE-2026-18556 yet — track the N-able N-central advisory for a fixed release and apply the workarounds below in the meantime.

How do I detect CVE-2026-18556 across my infrastructure?

Inventory every N-able N-central deployment and check each version against the affected-products list above.

How do I mitigate CVE-2026-18556 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

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

No public exploit code has been indexed for CVE-2026-18556 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

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

CVE-2026-18556 has an EPSS (Exploit Prediction Scoring System) score of 7.9%, placing it in the 95th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

Is CVE-2026-18556 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2026-18556 (N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-08-04. CISA required all US federal civilian agencies to remediate this vulnerability by 2026-08-07. The required action was: 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. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2026-18556?

CVE-2026-18556 is classified as CWE-288 (CWE-288). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2026-18556?

CVE-2026-18556 affects N-able N-central (1 version, e.g. 0). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2026-18556 published, and has it been updated?

CVE-2026-18556 was published on August 1, 2026 and was last updated on August 5, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV · ACTIVELY EXPLOITED

CVE-2026-18556 — N-Central

CVE-2026-18556 is a CWE-288 vulnerability in N-able N-central. It is in CISA's Known Exploited Vulnerabilities catalog (added 2026-08-04) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

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.

Published

Aug 1, 2026

Updated

Aug 5, 2026

Affected

1 product

Patched

See advisory

Exploits

None indexed

Exploitation data as of Oct 29, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-08-04. Federal agencies were required to remediate by 2026-08-07.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2026-18556.

EPSS Exploitation Probability

via FIRST.org ↗

7.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs95th percentile — riskier than 95% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

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.

Affected Products

1 product · 1 configurations

Application

N-centralN-able

≤ 2026.1

1 version

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every N-able N-central deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2026-18556 yet — track the N-able N-central advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

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.

O3 Security · Runtime Protection

Is CVE-2026-18556 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

Protect my workloads How runtime protection works