Cyber Resilience

CVE-2026-20086

Published
25 March 2026
Modified
26 March 2026
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0035 28th percentile
Risk Priority 61 floored blend · peak EPSS

Summary

CVE-2026-20086 is a high-severity Improper Handling of Missing Values (CWE-230) vulnerability in Cisco IOS XE (inferred from references). Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 28th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-20086 is a vulnerability in the processing of Control and Provisioning of Wireless Access Points (CAPWAP) packets within Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family. The issue arises from improper handling of malformed CAPWAP packets, which could allow an unauthenticated, remote attacker to trigger a denial-of-service (DoS) condition. It has a CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) and is associated with CWE-230: Improper Handling of Missing Special Element.

An unauthenticated, remote attacker can exploit this vulnerability by sending a specially crafted, malformed CAPWAP packet to an affected device. Successful exploitation would cause the device to reload unexpectedly, leading to a DoS condition that disrupts wireless network operations until the device is manually restarted.

The Cisco Security Advisory provides details on mitigation and patch information at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wlc-dos-hnX5KGOm. Security practitioners should consult this advisory for software updates and workarounds applicable to the Catalyst CW9800 Family.

EU & UK References

Vulnerability Data

A vulnerability in the processing of Control and Provisioning of Wireless Access Points (CAPWAP) packets of Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS)…

more

condition on an affected device. This vulnerability is due to improper handling of a malformed CAPWAP packet. An attacker could exploit this vulnerability by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS condition.

CWE(s)
CWE-230

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-0048Shared CWE-230
CVE-2024-11024Shared CWE-230
CVE-2026-1461Shared CWE-230
CVE-2024-9781Shared CWE-230
CVE-2023-1697Shared CWE-230
CVE-2024-6237Shared CWE-230
CVE-2024-10508Shared CWE-230
CVE-2024-0208Shared CWE-230
CVE-2026-25659Shared CWE-230
CVE-2026-25658Shared CWE-230

Affected Assets

Cisco
IOS XE
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 7 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

Input validation directly requires checking that supplied parameters/fields have valid (non-missing) values before they are used.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and null/missing-value handling during coding and review.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect missing-value flaws but does not itself prevent them.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate explicit handling of missing parameter values.

A.8.28 Secure coding partial match
prevents

Secure coding standards can require validation that every supplied parameter has a non-null value.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (4 rules)
  • V-248714 OL 8 must not allow accounts configured with blank or null passwords. prevents CWE-230
  • V-248715 OL 8 must not allow blank or null passwords in the system-auth file. prevents CWE-230
  • V-248716 OL 8 must not allow blank or null passwords in the password-auth file. prevents CWE-230
RHEL 7 (1 rule)
  • V-204424 The Red Hat Enterprise Linux operating system must not allow accounts configured with blank or null passwords. prevents CWE-230
Ubuntu 24.04 (1 rule)
  • V-270714 Ubuntu 24.04 LTS must not allow accounts configured in Pluggable Authentication Modules (PAM) with blank or null passwords. prevents CWE-230

References