Security readout for executives and security teams
Plain-English summary
This issue affects Cisco Small Business 100, 300, and 500 Series wireless access points. An attacker who already has valid administrative credentials could send crafted web management requests and run commands as root. The credential requirement lowers likelihood, but compromise of an admin account could turn into full device control.
Executive priority
Treat this as a moderate-priority infrastructure hygiene issue. It is not reported as actively exploited in the supplied sources, but a compromised admin account could lead to full access point control. Prioritize internet-exposed or broadly reachable management interfaces first.
Technical view
CVE-2021-1555 is a CWE-77 command injection issue in the web-based management interface. Improper validation of user input allows an authenticated remote administrator to execute arbitrary commands with root privileges via crafted HTTP requests. The CVSS v3.1 score is 4.7, reflecting high privileges required and limited confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most relevant for organizations still operating Cisco Small Business 100, 300, or 500 Series wireless access points with web management reachable by administrators. Risk increases if administrative credentials are shared, weak, reused, or exposed through another incident.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. Exploitation requires valid administrative credentials and network access to the web-based management interface. The impact is serious after authentication because commands may run as root on the device.
Researcher notes
The source bundle identifies the affected product family but does not provide exact vulnerable versions, fixed releases, or proof-of-concept details. Validation should therefore anchor on Cisco’s advisory and local device inventory. Avoid assuming exposure from product name alone without model and software confirmation.
Mitigation direction
- Review Cisco’s advisory for affected models and any fixed software guidance.
- Upgrade or replace affected access points according to Cisco’s published guidance.
- Restrict web management access to trusted administrator networks only.
- Review administrative accounts and remove shared, stale, or unnecessary credentials.
- Monitor management interface access for unusual authenticated requests.
Validation and detection
- Inventory Cisco Small Business 100, 300, and 500 Series wireless access points.
- Confirm whether web-based management is enabled and who can reach it.
- Compare each device model and software state against Cisco’s advisory.
- Review admin account lists for unnecessary or exposed credentials.
- Check logs for unexpected authenticated 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-77: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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-2021-1555 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
- Medium
- CVSS
- 4.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
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:L/I:L/A:L1.23.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.7MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- 20210519 Cisco Small Business 100, 300, and 500 Series Wireless Access Points Command Injection 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.
Improper Neutralization of Special Elements used in a Command ('Command Injection')
Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.