Cisco Small Business RV Series Routers Vulnerabilities (CVE-2022-20708)
Published In CISA KEV since Sources: CVE.org
What is affected, what to do
A stack-based buffer overflow vulnerability in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers allows an attacker to execute arbitrary code, elevate privileges, execute arbitrary commands, bypass authentication, run unsigned software, or cause a denial of service (DoS). This vulnerability is actively exploited, as indicated by its listing in the CISA KEV catalog. Affected products include specific firmware versions (1.0.03.24) of these routers. Immediate action is required to update the affected devices to the latest firmware version to mitigate the risk.
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 Rv340 Firmware
lte *..1.0.03.24 - Cisco Rv340w Firmware
lte *..1.0.03.24 - Cisco Rv345 Firmware
lte *..1.0.03.24 - Cisco Rv345p Firmware
lte *..1.0.03.24
- Cisco Rv340 Firmware
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Metrics
10.0
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
10.0
CVSS v3
Severity Critical on the scale from 0 to 10.
Source: CVE.org
14.9 %
EPSS score
Elevated — model estimates 10-50% exploitation likelihood.
Source: FIRST EPSS, percentile 96.7
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- 225.21 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- 10.0 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- 10.0
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- 14.9 %
- Elevated — model estimates 10-50% 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.
Read in glossary- 96.7
- 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 29 October 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-121
Response and mitigation
Why act now?
Prioritisation rationale
This CVE is on KEV because Cisco RV routers are widespread in SMEs, branches and home offices, and public exploit chains exist. Attackers typically use these devices for botnets, proxy infrastructure and as a foothold into the internal network. Exploitation requires adjacent-network access and low privileges, but it yields full device takeover with maximum impact on confidentiality, integrity and availability. Exploitation likelihood is high, and CISA has no ransomware use on record. Rate it critical wherever guest or third-party devices share a segment with the management interface or remote management is enabled; in strictly segmented environments rate it high, with a patch window of a few days.
Runbook step 1
Immediate response (0-24 h)
- Inventory: Find every Cisco Small Business RV160, RV260, RV340, RV340W, RV345 and RV345P, including branch offices, home offices and MSP-managed sites. Record the firmware version on each one; the context explicitly lists 1.0.03.24 as affected.
- Patch: A fixed release is available from the vendor. Look up the exact version in the Cisco Small Business RV Series security advisory. Download firmware only from the official Cisco software portal and verify the hash, because one of the bundled flaws allows unsigned software to be fetched and run.
- Disable Remote Management: Turn off WAN-side access to the web management interface (HTTP/HTTPS) on all affected units now. The scored vector is adjacent-network, but an internet-exposed admin UI widens the attack surface considerably.
- Restrict LAN-side admin access: Allow the management UI only from a dedicated admin VLAN or named admin hosts. Low privileges are enough to exploit this, so any guest or untrusted client in the same segment is a viable attacker.
- Rotate secrets: Change local router accounts, VPN pre-shared keys, certificates and RADIUS/LDAP shared secrets held on unpatched devices. Because authentication and authorization bypass is possible, treat these secrets as exposed.
- Preserve evidence: Before patching a suspicious unit, export its configuration, syslog buffer and diagnostics. If you suspect compromise, factory-reset and rebuild the device rather than upgrading in place.
Runbook step 2
Mitigation layers
- Network segmentation: Keep guest Wi-Fi, IoT and BYOD strictly away from router management IPs. Use upstream switch ACLs or router ACLs to permit TCP 80/443 to router interfaces from the admin VLAN only.
- Perimeter: Block inbound traffic to the RV management ports at the ISP edge or an upstream firewall. Check how your public IPs appear in internet scan data (Shodan, Censys).
- IPS/IDS: Where you can place a sensor in front of the device, enable the Suricata/Snort vendor signatures that reference this Cisco RV advisory and CVE-2022-20708. Flag HTTP POSTs to the admin UI that carry oversized or metacharacter-laden parameters.
- Egress control: At the next enforcement point, block outbound HTTP, TFTP and FTP connections that originate from the router itself. This makes payload staging and unsigned-software retrieval harder.
- Configuration hardening: Disable unused services (SSL VPN, UPnP, remote management), forward syslog to a central collector, and configure NTP so timestamps can be correlated.
- Lifecycle: If a unit cannot be patched promptly, schedule its replacement with a centrally managed firewall that separates the management plane. For NIS2/KRITIS, document the risk acceptance and the compensating controls in place until then.
Runbook step 3
Detection rules
- Admin UI access: Use firewall logs or Zeek
http.logto find POSTs to router management IPs from non-admin segments, especially those with long parameters or shell metacharacters (;,|,`,$(). Example SPL:index=zeek sourcetype=http dest_ip IN (<rv_mgmt_ips>) method=POST NOT src_ip IN (<admin_hosts>) - Router-originated egress: In NetFlow or Zeek
conn.log, look for sessions where the router IP is the client and the destination is an unknown external host (wget/curl/TFTP patterns, unusual ports). A router acting as a client is a high-fidelity anomaly. - Syslog: Alert on new or modified local accounts, config changes outside maintenance windows, unexpected reboots or web-server crashes (a sign of failed overflow attempts), and firmware-upgrade events without a matching change ticket.
- Suricata alerts: Escalate hits on ET or Talos rules for Cisco RV command injection or overflow with high priority. Sigma shape:
logsource: product=suricata,selection: alert.signature|contains: 'Cisco RV'. - Config drift: Export the running config on a schedule and diff it against a baseline. Pay particular attention to new port forwards, DNS changes, VPN peers and static routes.
- Admin UI access: Use firewall logs or Zeek
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
Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an attacker to do any of the following: Execute arbitrary code Elevate privileges Execute arbitrary commands Bypass authentication and authorization protections Fetch and run unsigned software Cause denial of service (DoS) For more information about these vulnerabilities, see the Details section of this advisory.
Source: NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)
Vendors and products
Affected operating systems
| Other | cisco | rv340_firmware | — |
| Other | cisco | rv340w_firmware | — |
| Other | cisco | rv345_firmware | — |
| Other | cisco | rv345p_firmware | — |
Weakness classes (CWE)
CWE-121Stack-based Buffer Overflow
Variant
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
Entry at MITRE CWE-121
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
- tools.cisco.com20220203 Cisco Small Business RV Series Routers VulnerabilitiesVendor advisory, x_refsource_CISCO, Vendor advisory
- zerodayinitiative.comadvisories/ZDI-22-417x_refsource_MISC, Third-party advisory, Vulnerability database
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2022-20708government-resource, US government resource
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