Security readout for executives and security teams
Plain-English summary
CVE-2021-1327 affects the web management interface of several Cisco Small Business RV routers. An attacker with valid administrator credentials could make the router run code as root or restart unexpectedly. The main business risk is compromise or outage of edge networking equipment if administrative access is exposed or credentials are stolen.
Executive priority
Treat this as high priority for small office or branch environments using these routers, especially if remote management is enabled. The vulnerability requires admin credentials, but successful abuse can compromise routing infrastructure or disrupt connectivity.
Technical view
Cisco describes improper validation of user-supplied input in crafted HTTP requests to the web-based management interface. A successful authenticated remote attack can execute arbitrary code as root or trigger a reload. CVSS 3.1 is 7.2, with network attack vector, low complexity, high privileges required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely where affected Cisco RV016, RV042, RV042G, RV082, RV320, or RV325 routers are still deployed and their web management interface is reachable by administrators over a network path an attacker could access.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation requires valid administrator credentials, but impact is severe because successful execution runs as root or can cause denial of service.
Researcher notes
The key constraint is PR:H: attacks require valid administrator credentials. Validation should focus on device presence, firmware status, management-plane reachability, and administrative credential exposure. The provided bundle does not include patch version details or exploit evidence beyond Cisco’s vulnerability description.
Mitigation direction
- Check Cisco’s advisory for affected firmware status and vendor remediation guidance.
- Limit web management access to trusted administrative networks only.
- Audit and protect administrator credentials for affected routers.
- Remove unnecessary remote management exposure where operationally possible.
- Plan replacement if vendor guidance shows no supported fixed firmware.
Validation and detection
- Inventory Cisco RV016, RV042, RV042G, RV082, RV320, and RV325 devices.
- Identify firmware versions and compare them with Cisco advisory guidance.
- Confirm whether web management is reachable from untrusted networks.
- Review administrative account use, credential storage, and recent login activity.
- Validate monitoring for unexpected router reloads or configuration changes.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
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CWE-121: Exact CWE lookup
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Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-1327 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H1.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.2HighVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210203 Cisco Small Business RV Series Routers Management Interface Remote Command Execution and Denial of Service VulnerabilitiesCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.