CVE-2021-1554 | Cisco Small Business 100, 300, and 500 Series Wireless Access Points Command Injection Vulnerabilities

Multiple vulnerabilities in the web-based management interface of certain Cisco Small Business 100, 300, and 500 Series Wireless Access Points could allow an authenticated, remote attacker to perform command injection attacks against an affected device. These vulnerabilities are due to improper validation of user-supplied input. An attacker could exploit these vulnerabilities by sending crafted HTTP requests to the web-based management interface of an affected system. A successful exploit could allow the attacker to execute arbitrary commands with root privileges on the device. To exploit these vulnerabilities, the attacker must have valid administrative credentials for the device.

Published: 2021-05-22 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-1554 is rated Moderate Risk (45/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.58%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-1554

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.60% 1.58% +0.98%
2 2026-05-24 0.74% 0.60% -0.14%
3 2025-11-21 0.74%

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1554

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.7 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
1.2 3.4 [email protected]
7.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.2 5.9 [email protected]
9.0 2.0 HIGH
AV:N/AC:L/Au:S/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
8.0 10.0 [email protected]

Weakness enumeration for CVE-2021-1554

Affected software / configurations for CVE-2021-1554

Vendor Product Version Raw CPE
cisco wap125_firmware <= 1.0.3.1 cpe:2.3:o:cisco:wap125_firmware:*:*:*:*:*:*:*:*
cisco wap131_firmware <= 1.0.2.17 cpe:2.3:o:cisco:wap131_firmware:*:*:*:*:*:*:*:*
cisco wap150_firmware <= 1.1.2.4 cpe:2.3:o:cisco:wap150_firmware:*:*:*:*:*:*:*:*
cisco wap351_firmware <= 1.0.2.17 cpe:2.3:o:cisco:wap351_firmware:*:*:*:*:*:*:*:*
cisco wap361_firmware <= 1.1.2.4 cpe:2.3:o:cisco:wap361_firmware:*:*:*:*:*:*:*:*
cisco wap581_firmware <= 1.0.3.1 cpe:2.3:o:cisco:wap581_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-1554

cvelogic Threat Intelligence