Security readout for executives and security teams
Plain-English summary
CVE-2021-1338 affects Cisco Small Business RV016, RV042, RV042G, RV082, RV320, and RV325 routers. An attacker with valid administrator credentials could use the management interface to run code as root or force a restart. The main business risk is router takeover or outage where these devices remain in use.
Executive priority
Treat as high priority for environments still using these routers. The vulnerability requires admin credentials, but impact is severe because compromise can reach root-level router control or disrupt connectivity.
Technical view
The issue is improper validation of user-supplied input in the web-based management interface, mapped to CWE-121. The CVSS 3.1 score is 7.2 high, with network access, low complexity, high privileges, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to organizations still operating the listed Cisco Small Business RV Series routers, especially where the web management interface is reachable by administrators over a network. Valid administrator credentials are required, so stolen, shared, or weak admin access materially increases risk.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires authenticated administrator access and crafted HTTP requests to the management interface. A successful attack could run arbitrary code as root or reload the device, causing denial of service.
Researcher notes
Do not assume unauthenticated exposure from the provided evidence. Focus validation on model presence, firmware state, administrative access paths, and management interface reachability. Patch details are not included in the bundle beyond the Cisco advisory reference.
Mitigation direction
- Identify whether listed Cisco RV router models remain deployed.
- Check Cisco's advisory for affected releases and fixed firmware guidance.
- Restrict management interface access to trusted administrative networks.
- Review and tighten administrator credential controls.
- Retire unsupported or unpatchable devices from sensitive networks.
Validation and detection
- Inventory RV016, RV042, RV042G, RV082, RV320, and RV325 devices.
- Compare device firmware status against Cisco's advisory.
- Verify management interfaces are not broadly reachable.
- Confirm only authorized administrators have valid credentials.
- Review device logs for unexpected reloads or suspicious admin 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-2021-1338 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.