Cisco VPN Routers Remote Code Execution Vulnerability (CVE-2018-0125)
Published In CISA KEV since Sources: CVE.org
What is affected, what to do
A vulnerability in the web interface of the Cisco RV132W ADSL2+ Wireless-N VPN and RV134W VDSL2 Wireless-AC VPN Routers could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system, including issuing commands with root privileges. The attacker could also cause an affected system to reload, resulting in a denial of service (DoS) condition.
The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.
- Affected
- Cisco RV132W and RV134W
eq Cisco RV132W and RV134W..Cisco RV132W and RV134W
- Cisco RV132W and RV134W
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Metrics
9.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
9.8
CVSS v3
Severity Critical on the scale from 0 to 10.
Source: CVE.org
55.2 %
EPSS score
High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
Source: FIRST EPSS, percentile 99.03
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- 227.46 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 exploited
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.
Read in glossary- 9.8 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- 9.8
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“.
Read in glossary- 55.2 %
- High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
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.
Read in glossary- 99.03
- 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 · automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 8 November 2024
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
This flaw is network-reachable without authentication, has low attack complexity and yields root on a perimeter device, which puts it in the most severe class possible. Its exploitation likelihood ranks among the highest of all known CVEs. SOHO VPN routers like these are mass-scanned and routinely conscripted into botnets, residential-proxy networks or DNS-manipulation schemes. CISA does not flag known ransomware use, but a compromised edge router still makes an excellent foothold into internal networks and VPN tunnels. Treat any internet-exposed management interface as top priority with a 24-hour remediation target, and internal-only exposure as high priority. For NIS2/KRITIS branch sites and suppliers, replacing end-of-life units is the only durable fix.
Runbook step 1
Immediate response (0-24 h)
- Inventory: Locate every Cisco RV132W (ADSL2+ Wireless-N VPN) and RV134W (VDSL2 Wireless-AC VPN) router, including branch offices, home offices and third-party-managed sites. Use CMDB, DHCP leases, MAC OUI matching and Shodan/Censys lookups of your own public ranges. Record the firmware version from the web GUI or via SNMP.
- Upgrade firmware: Upgrade to firmware 1.0.1.11 or later (Cisco Bug IDs CSCvg92737, CSCvh60170). Download only from Cisco's official software portal and verify the hash. Check the hardware lifecycle (end-of-sale/end-of-life) status in the vendor advisory and schedule replacement for legacy units.
- Kill remote management: Disable WAN-side web management (Remote Management) immediately. Block internet access to HTTP/HTTPS (TCP 80/443, or the configured remote-management port) on the upstream perimeter.
- Assume compromise where exposed: Treat any device whose web interface was internet-reachable as potentially compromised. Export its configuration and diff it against a known-good baseline. Look for rogue admin accounts, altered DNS servers, new port forwards and unknown VPN peers.
- Rotate secrets: After upgrading or rebuilding, rotate every secret stored on the device: admin password, IPsec PSKs, Wi-Fi keys, PPPoE/DSL credentials and SNMP communities. If compromise is suspected, factory-reset and rebuild the configuration by hand rather than restoring a backup.
Runbook step 2
Mitigation layers
- Network segmentation: Restrict the management interface to a dedicated management VLAN or admin subnet. ACL-block guest Wi-Fi and user subnets from reaching the router's LAN IP on TCP 80/443, because the flaw needs no authentication and is exploitable from inside too.
- Perimeter and IPS: Have upstream firewalls drop inbound HTTP(S) to router WAN addresses. Also enable IPS signatures covering CVE-2018-0125 (Cisco Talos/Snort ruleset, Suricata ET rules). Look up the SID in your current ruleset.
- Egress filtering: Restrict connections originating from the router itself to what it actually needs (DNS, NTP, update servers, VPN peers). This frustrates reverse shells, botnet C2 and proxy abuse.
- Replace the device: Where patching isn't possible or the unit is end-of-life, replace it with a supported platform. In the interim, put the router into pure modem/bridge mode and move routing, VPN and firewalling to a maintained firewall.
- Hardening: Disable unused services (UPnP, WPS, remote management, WAN-side Telnet/SSH). Allow HTTPS only for local management. Forward syslog to the SIEM.
Runbook step 3
Detection rules
- Network telemetry (Zeek/Suricata): Flag inbound HTTP POSTs from external sources to router IPs that carry unusually long parameters or bodies, since the root cause is incomplete input validation. Sigma shape:
http.method=POST AND dst_ip IN router_ips AND src_ip NOT IN mgmt_nets AND request_body_len > 1024. - Firewall/NetFlow: Flag outbound sessions initiated by the router to unknown destinations or unusual ports, such as reverse-shell, IRC or C2 ports. KQL sketch:
CommonSecurityLog | where SourceIP in (router_ips) and DestinationPort !in (53,123,443,500,4500). - Device syslog: Watch for unexpected reboots or reloads (possible DoS or a failed exploit attempt), config changes outside maintenance windows, and admin logins from foreign IPs. SPL:
index=network host IN (rv13*) ("reboot" OR "config changed" OR "login") | stats count by src_ip. - Config drift: Back up configs daily and diff them. Alert on changed DNS servers, new port forwards, re-enabled remote management or new IPsec peers.
- DNS telemetry: Clients behind an affected router that suddenly switch to unfamiliar resolvers point to post-compromise DNS hijacking.
- Network telemetry (Zeek/Suricata): Flag inbound HTTP POSTs from external sources to router IPs that carry unusually long parameters or bodies, since the root cause is incomplete input validation. Sigma shape:
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
A vulnerability in the web interface of the Cisco RV132W ADSL2+ Wireless-N VPN and RV134W VDSL2 Wireless-AC VPN Routers could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system, including issuing commands with root privileges. The attacker could also cause an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to an incomplete input validation on user-controlled input in an HTTP request to the targeted device. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected system. A successful exploit could allow the attacker to execute arbitrary code as the root user and gain full control of the affected system or cause it to reload, resulting in a DoS condition. This vulnerability is fixed in firmware version 1.0.1.11 for the following Cisco products: RV132W ADSL2+ Wireless-N VPN Router and RV134W VDSL2 Wireless-AC VPN Router. Cisco Bug IDs: CSCvg92737, CSCvh60170.
Source: NVD (NIST), cvelistv5, CISA KEV Catalog
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| — | Cisco RV132W and RV134W |
|
|
Vendors and products
Affected operating systems
| Other | cisco | rv132w_firmware | 1.0 |
| Other | cisco | rv134w_firmware | 1.0 |
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.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited |
References & sources
- securityfocus.com103140Vulnerability database, x_refsource_BID, Broken link, Third-party advisory, Vulnerability database
- tools.cisco.comsecurity/center/content/CiscoSecurityAdvisory/cisco-sa-20180207…x_refsource_CONFIRM, Broken link, Vendor advisory
- securitytracker.com1040336Vulnerability database, x_refsource_SECTRACK, Broken link, Third-party advisory, Vulnerability database
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0125government-resource, US government resource
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<a href="https://intel.neosec.eu/en/cve/CVE-2018-0125"><img src="https://intel.neosec.eu/badge/cve/CVE-2018-0125.svg?lang=en" alt="CVE-2018-0125 – NEOSEC Intel" height="20"></a>