CVE-2016-9221

A Denial of Service Vulnerability in 802.11 ingress connection authentication handling for the Cisco Mobility Express 2800 and 3800 Access Points (APs) could allow an unauthenticated, adjacent attacker to cause authentication to fail. Affected Products: This vulnerability affects Cisco Mobility Express 2800 Series and 3800 Series Access Points when configured in local mode in 40 MHz. More Information: CSCvb33575. Known Affected Releases: 8.2(121.12) 8.4(1.82). Known Fixed Releases: 8.2(131.2) 8.2(131.3) 8.2(131.4) 8.2(141.0) 8.3(104.53) 8.3(104.54) 8.4(1.80) 8.4(1.85).

Published: 2017-01-26 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-9221 is rated Low Risk (31.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.54%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2016-9221

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 0.29% 0.54% +0.25%
2 2026-03-13 0.39% 0.29% -0.10%
3 2025-03-30 — 0.39% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-9221

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.0 MEDIUM
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
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:N)
No account or special rights needed—anonymous or random user is enough.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 1.4 [email protected]
3.3 2.0 LOW
AV:A/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:A)
Requires access to an adjacent network segment.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.5 2.9 [email protected]

Weakness enumeration for CVE-2016-9221

Affected software / configurations for CVE-2016-9221

Vendor Product Version Raw CPE
cisco aironet_access_point_software 8.2\(121.12\) cpe:2.3:o:cisco:aironet_access_point_software:8.2\(121.12\):*:*:*:*:*:*:*
cisco aironet_access_point_software 8.4\(1.82\) cpe:2.3:o:cisco:aironet_access_point_software:8.4\(1.82\):*:*:*:*:*:*:*

References for CVE-2016-9221

cvelogic Threat Intelligence