Security readout for executives and security teams
Plain-English summary
This vulnerability affects Cisco Small Business RV-series routers. Someone who already has administrator credentials could abuse the web management interface to run code as root or force the router to restart. That makes compromised admin accounts much more dangerous, especially for routers exposed to untrusted networks or used in small-office edge connectivity.
Executive priority
Treat this as a high-priority edge-device risk if affected routers remain in service. The attacker needs admin credentials, but successful exploitation can mean full device control or outage. Prioritize internet-facing or remotely administered routers first.
Technical view
Cisco reports improper validation of user-supplied input in the web-based management interface. Authenticated remote administrators can send crafted HTTP requests that may execute arbitrary code as root or trigger a device reload. The CVSS 3.1 score is 7.2 with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely where Cisco RV016, RV042, RV042G, RV082, RV320, or RV325 routers are still deployed and their management interfaces are reachable by administrators over a network. The source bundle does not provide affected firmware version ranges.
Exploitation context
The sources require valid administrator credentials. The CVE is not listed as KEV in the provided bundle, and no cited source here confirms active exploitation. Risk rises if admin credentials are shared, weak, reused, or the management interface is broadly reachable.
Researcher notes
The public summary identifies CWE-121 and input validation failure in the web management interface. The bundle does not include fixed version details, proof-of-concept status, or exploit telemetry. Avoid assuming unauthenticated exposure; the stated prerequisite is valid administrator credentials.
Mitigation direction
- Check Cisco's advisory for fixed firmware and vendor-directed remediation.
- Restrict web management access to trusted administrative networks only.
- Review and harden administrator accounts, passwords, and access paths.
- Remove or replace unsupported affected routers where vendor fixes are unavailable.
- Monitor for unexpected router reloads or unauthorized administrative changes.
Validation and detection
- Inventory Cisco RV016, RV042, RV042G, RV082, RV320, and RV325 devices.
- Confirm each device firmware against Cisco's advisory guidance.
- Verify the management interface is not broadly internet reachable.
- Review admin account lists for stale, shared, or unnecessary access.
- Check device logs for unexplained reloads or management activity.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-121: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 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-2021-1321 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
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.