# CVE-2026-18577 — N-able N-central

**CISA KEV**

> As of 2026-08-03, CVE-2026-18577 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in N-able N-central, CVSS v4.0 8.2, EPSS 1.4% (71.3th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-08-03), with a US federal remediation deadline of 2026-08-06. Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-18577, most recently “N-able N-central Authentication Bypass Flaws (CVE-2026-18556, CVE-2026-18577) Actively Exploited for Admin Access and Cloudflare Tunnel Persistence”.

**Last updated:** 2026-08-03

## What is CVE-2026-18577?

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

The record classifies CVE-2026-18577 under weakness class [CWE-288](https://cwe.mitre.org/data/definitions/288.html). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 42 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 8.2 — High (derived from score) (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:L/SA:L/E:A`)
- **EPSS (FIRST):** 1.4% probability of exploitation in the next 30 days, higher than 71.3% of all scored CVEs
- **CISA KEV:** Listed since 2026-08-03, federal remediation deadline 2026-08-06
- **Threadlinqs priority:** 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- **Published:** 2026-08-02, last modified 2026-08-03

## Is CVE-2026-18577 being exploited?

CISA added CVE-2026-18577 to the Known Exploited Vulnerabilities catalog on 2026-08-03, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-08-06 under BOD 22-01. It currently carries a trending score of 58 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **N-able**: N-central

## How to fix CVE-2026-18577

Because CVE-2026-18577 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-08-06. No vendor patch reference has been recorded for CVE-2026-18577 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-18577

2 tracked threats in the Threadlinqs corpus reference CVE-2026-18577, either in the campaign’s CVE list or as an indicator on the campaign record.

- [N-able N-central Authentication Bypass Flaws (CVE-2026-18556, CVE-2026-18577) Actively Exploited for Admin Access and Cloudflare Tunnel Persistence](https://intel.threadlinqs.com/threat/TL-2026-1941) — HIGH · 2026-08-08
- [N-able N-central Authentication Bypass (CVE-2026-18577) Actively Exploited for Admin Takeover](https://intel.threadlinqs.com/threat/TL-2026-1830) — CRITICAL · 2026-08-03

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories. Last verified by Threadlinqs on 2026-08-03. This product uses the NVD API but is not endorsed or certified by the NVD.

**Other references**

- [documentation.n-able.com](https://documentation.n-able.com/N-central/Release_Notes/GA/Content/N-central_2026.3_HF1_Release_Notes.htm)
- [status.n-able.com](https://status.n-able.com/2026/08/02/n-central-2026-3-hotfix-1-mitigation-for-cve-2026-18577/)
- [cve.org](https://www.cve.org/CVERecord?id=CVE-2026-18556)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-18577
Full detection coverage and IOCs for threats exploiting CVE-2026-18577 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp