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CVE-2021-1403

Cisco IOS XE Software Web UI Cross-Site WebSocket Hijacking Vulnerability

HIGH

7.4

CVSS Score

Published: March 24, 2021 at 08:07 PM UTC

Updated: June 17, 2026 at 03:31 AM UTC

1 product affected across 1 vendorIOS Xe

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Severity

HIGH7.4

Exploit prediction

EPSS 0.6%

SSVC

No known exploit

Description

A vulnerability in the web UI feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct a cross-site WebSocket hijacking (CSWSH) attack and cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient HTTP protections in the web UI on an affected device. An attacker could exploit this vulnerability by persuading an authenticated user of the web UI to follow a crafted link. A successful exploit could allow the attacker to corrupt memory on the affected device, forcing it to reload and causing a DoS condition.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

IOS Xe · Cisco

95%

16.10.1 16.10.1a 16.10.1b 16.10.1c 16.10.1d 16.10.1e 16.10.1f 16.10.1g 16.10.1s 16.10.2 16.10.3 16.11.1 16.11.1a 16.11.1b 16.11.1c 16.11.1s 16.11.2 16.12.1 16.12.1a 16.12.1c 16.12.1s 16.12.1t 16.12.1w 16.12.1x 16.12.1y 16.12.1z 16.12.1za 16.12.2 16.12.2a 16.12.2s 16.12.2t 16.12.3 16.12.3a 16.12.3s 16.12.4 16.12.4a 16.3.1 16.3.10 16.3.11 16.3.1a 16.3.2 16.3.3 16.3.4 16.3.5 16.3.5b 16.3.6 16.3.7 16.3.8 16.3.9 16.4.1 16.4.2 16.4.3 16.5.1 16.5.1a 16.5.1b 16.5.2 16.5.3 16.6.1 16.6.2 16.6.3 16.6.4 16.6.4a 16.6.4s 16.6.5 16.6.5a 16.6.5b 16.6.6 16.6.7 16.6.7a 16.6.8 16.7.1 16.7.1a 16.7.1b 16.7.2 16.7.3 16.7.4 16.8.1 16.8.1a 16.8.1b 16.8.1c 16.8.1d 16.8.1e 16.8.1s 16.8.2 16.8.3 16.9.1 16.9.1a 16.9.1b 16.9.1c 16.9.1d 16.9.1s 16.9.2 16.9.2a 16.9.2s 16.9.3 16.9.3a 16.9.3h 16.9.3s 16.9.4 16.9.4c 16.9.5 16.9.5f 16.9.6 17.1.1 17.1.1a 17.1.1s 17.1.1t 17.1.2 17.1.3 17.2.1 17.2.1a 17.2.1r 17.2.1v 17.2.2 17.2.3 17.3.1 17.3.1a 17.3.1w 17.3.1x 17.3.2 17.3.2a 3.15.1xbs 3.15.2xbs

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-cswsh-FKk9AzT5

References (1)

Vendor Advisoryx_refsource_CISCO

Source: [email protected]

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-cswsh-FKk9AzT5

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.4HIGHcisco

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: REQUIRED
Scope: CHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-345CWE-1021

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