LiveActive security incident?Get immediate response
CVE Record

CVE-2021-1156: Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers Management Interface Stored Cross-Site Scripting Vulnerabilities

Multiple vulnerabilities in the web-based management interface of Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers could allow an authenticated, remote attacker to conduct cross-site scripting (XSS) attacks against a user of the interface. The vulnerabilities are due to insufficient input validation by the web-based management interface. An attacker could exploit these vulnerabilities by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information. To exploit these vulnerabilities, an attacker would need to have valid administrator credentials on the affected device.

MediumCVSS 4.8Not KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This issue affects the management interface of several Cisco Small Business RV routers. An attacker who already has administrator credentials could store script content that runs in another interface user's browser, potentially exposing browser-based information tied to that router session.

Executive priority

Handle this as a controlled remediation item, not an emergency, unless affected router management interfaces are broadly exposed or administrator credentials are poorly governed. The business risk is session-level compromise of router administration rather than unauthenticated takeover.

Technical view

CVE-2021-1156 is a stored XSS flaw caused by insufficient input validation in Cisco RV110W, RV130, RV130W, and RV215W web management interfaces. Exploitation is network reachable but requires administrator privileges and user interaction. Successful exploitation can execute script in the interface context or access sensitive browser-based information.

Likely exposure

Exposure is most likely in environments still operating Cisco RV110W, RV130, RV130W, or RV215W routers with the web management interface accessible to administrators. Risk increases where admin accounts are shared, weakly controlled, or the management interface is reachable from untrusted networks.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. The attacker must have valid administrator credentials and convince or wait for a user of the affected interface to encounter the stored script condition.

Researcher notes

CVSS v3.1 is 4.8: AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N. CWE-79 applies. The evidence bundle does not provide exact affected firmware versions, CPEs, fixed releases, or workaround details beyond the Cisco advisory reference.

Mitigation direction

  • Check the Cisco advisory for affected firmware and vendor-supported fixes or workarounds.
  • Restrict router management interfaces to trusted administrative networks only.
  • Review and reduce administrator accounts on affected routers.
  • Use unique, controlled administrator credentials for each device.
  • Plan replacement if affected devices are unsupported by current Cisco guidance.

Validation and detection

  • Inventory Cisco RV110W, RV130, RV130W, and RV215W routers in the environment.
  • Confirm each device firmware against Cisco advisory guidance.
  • Verify the management interface is not reachable from untrusted networks.
  • Review administrator account lists for unnecessary or shared access.
  • Check router management logs for unexpected administrative activity.
Prepared
Confidence
high
Sources
3

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-1156 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
4.8CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N1.72.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.8Medium
CVSS 3.1 vector shape for CVE-2021-1156Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Small Business RV Series Router Firmwaren/aListed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-79 · source CWE mapping

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.