CriticalCVE-2025-8876

    Command Injection Vulnerability (CVE-2025-8876)

    Published In CISA KEV since Sources: pwn.watch, CVE.org

    What is affected, what to do

    Improper Input Validation vulnerability in N-able N-central allows OS Command Injection.This issue affects N-central: before 2025.3.1.

    The vulnerability is being actively exploited; treat it as a priority. Update N-able N-central to version 2025.3.1. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • N-able N-central lt *..2025.3.1
    Fixed in
    • N-able N-central 2025.3.1

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    9.4

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v4

    8.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: pwn.watch, CVE.org

    4.1 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 90.8

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    223.30 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

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    9.4 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    8.8
    CVSS v4

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    9.4
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

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    4.1 %
    Moderate — model estimates 1-10% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

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    90.8
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 14 August 2025
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-20

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw is network-reachable with low complexity and needs only a low-privilege account. Successful exploitation fully compromises the server's confidentiality, integrity and availability, and its exploitation likelihood is markedly higher than for most CVEs. What makes it dangerous is N-central's role as an RMM platform: attackers use such systems as a force multiplier, pushing code from one server to every managed endpoint. That makes MSPs, their customers and internal IT departments prime targets. CISA does not flag known ransomware use, but the supply-chain blast radius is severe. Treat it as critical with a 24-hour patch target if your instance is internet-exposed or has many or shared accounts. Internal-only instances with MFA still warrant high priority.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Patch now: Upgrade every on-premises N-central server to 2025.3.1 or later. All versions before 2025.3.1 are affected. For N-able-hosted instances, get written confirmation of patch status from the vendor or customer portal (useful evidence for NIS2 reporting).
      • Reduce exposure: Check whether the N-central web UI is reachable from the internet. Until patched, firewall admin access (UI/API) down to VPN and admin networks only. Keep agent communication open only as far as operations strictly require.
      • Audit accounts and rotate credentials: Exploitation requires an authenticated low-privilege account. Review all N-central users, disable stale or unknown accounts, enforce MFA everywhere, and rotate passwords and API tokens. Prioritise accounts shared with customers or third parties.
      • Compromise assessment before patching: Preserve logs, process lists and cron jobs from the N-central server (forensic copy or VM snapshot) before or alongside the upgrade. Patching does not undo an existing intrusion.
      • Check downstream endpoints: N-central is an RMM platform. A compromised server can push scripts and software to every managed endpoint. Review recently created or modified automation tasks, scripts and software deployments for legitimacy.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: Move the N-central server into a dedicated management zone. Allow inbound UI access only from admin jump hosts. Restrict the server's egress to known destinations (N-able update infrastructure, agent networks) and block arbitrary internet egress to stop reverse shells and payload staging.
      • WAF/reverse proxy: Publish the UI only behind a reverse proxy with pre-authentication, such as SSO/IdP with MFA. Enable WAF command-injection rules on request parameters covering ;, |, &&, $(, backticks and URL-encoded variants such as %3B and %7C.
      • IAM/least privilege: Separate technician and customer-portal roles from admin roles and apply least privilege. Minimise local N-central accounts in favour of central authentication with MFA.
      • Server hardening: Restrict shell capabilities of the web application's service account as far as possible, and avoid running it as root where the vendor supports this. Enable auditd execve monitoring for the application context. Keep offline, restorable backups of the N-central database.
      • Vendor guidance: Look up any further vendor-specific hardening in the N-able advisory for 2025.3.1. No permanent configuration workaround in lieu of the patch is documented.

    3. Runbook step 3

      Detection rules

      • Process ancestry (EDR/auditd): Watch for the N-central Java/Tomcat process spawning shells or tools such as sh, bash, curl, wget, nc, python or base64. Sigma shape: ParentImage|endswith: 'java' AND Image|endswith: ('/sh','/bash','/curl','/wget','/nc').
      • auditd: -a always,exit -F arch=b64 -S execve -F uid=<n-central-service-uid> -k ncentral_exec. Alert on anything outside the known baseline, such as shell commands containing pipes, redirects or downloads.
      • Web/proxy logs: Look for authenticated requests carrying shell metacharacters in parameters. SPL example: index=proxy dest=ncentral* | regex uri_query="(%3B|%7C|%60|\$\(|%24%28)". Correlate these with logins from unusual or rarely used accounts immediately beforehand.
      • Network telemetry (Zeek/Suricata): Flag new outbound connections from the N-central server to unknown external IPs, especially long-lived TCP sessions or executable downloads shortly after UI requests.
      • RMM abuse: Watch for sudden mass script or software deployments to many endpoints, or new scheduled tasks. On endpoints, look for the N-central agent as parent of powershell.exe -enc or cmd.exe /c with download cradles (Sysmon EID 1, Windows Event ID 4688).

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Improper Input Validation vulnerability in N-able N-central allows OS Command Injection.This issue affects N-central: before 2025.3.1.

    Source: pwn.watch, NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    N-ableN-central
    • < 2025.3.1
    • 2025.3.1
    n-ablen-central
    • < 2025.3.1
    • 2025.3.1

    Vendors and products

    Weakness classes (CWE)

    • CWE-20Improper Input Validation

      Class

      The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

      Entry at MITRE CWE-20

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited

    References & sources

    • status.n-able.comN-able advisory: N-able N-CentralRelease notes, pwn-watch
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-8876government-resource, US government resource
    • pwn.watchpwn.watch: N-able N-Central: 2 exploited vulnerabilities (CVE-2025-8875, CVE-2025-8876)pwn-watch
    • NVD (NIST)NVD: CVE-2025-8875pwn-watch
    • NVD (NIST)NVD: CVE-2025-8876pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch

    Linked advisories

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    Badge preview for CVE-2025-8876
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-8876"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-8876.svg?lang=en" alt="CVE-2025-8876 – NEOSEC Intel" height="20"></a>