CVE-2026-18577: N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 3 Aug 2026, 1 day after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 14.6%
EPSS score, percentile 96.6 of all scored records
- How severe?
- 8.2 High
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline 6 Aug 2026. Apply mitigations in accordance with vendor instructions … Full text
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 2026.3 and earlier
Unaffected 2026.3.1.7
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
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 due date for this action: 6 August 2026.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://documentation.n-able.com/N-central/Release_Notes/GA/Content/N-central_2026.3_HF1_Release_Notes.htm
- https://status.n-able.com/2026/08/02/n-central-2026-3-hotfix-1-mitigation-for-cve-2026-18577/
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-18577
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 2026.3 and earlier |
| Unaffected | 2026.3.1.7 |
Versions not listed are: unaffected.
Versions the record lists as unaffected: 2026.3.1.7.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2026-18577 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Aug 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 6 Aug 2026.
- The CVE record was published on 2 Aug 2026, 1 day before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 8.2 (High), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 14.6% (percentile 96.6), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
Incomplete patch leads to administrative account takeover
An incomplete patch for CVE-2026-18556 allows for authentication bypass and account takeover in N-central Versions through 2026.3.1
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-288: Authentication bypass using an alternate path or channel
Attack patterns (CAPEC)
- CAPEC-115: Authentication Bypass
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 2 Aug 2026 | CVE record published |
| 3 Aug 2026 | Added to CISA KEV |
| 4 Aug 2026 | CVE record last updated |
| 6 Aug 2026 | CISA due date for the required action |
References
More exploited N-able vulnerabilities
- CVE-2026-86218: N-able N-central Static Code Injection Vulnerability
- CVE-2026-18556: N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability
- CVE-2025-8875: N-able N-Central Insecure Deserialization Vulnerability
- CVE-2025-8876: N-able N-Central Command Injection Vulnerability