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

published 2021-03-24 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-6870

cvss: 7.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits: 0; none known

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.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-110-02 updated 2021-04-20 cvss 7.4

ICSA-21-110-02_Rockwell Automation Stratix Switches

Rockwell Automation Stratix 5400 <= 15.2(7)E3 Rockwell Automation Stratix 5410 <= 15.2(7)E3 Rockwell Automation Stratix 5700 <= 15.2(7)E3 Rockwell Automation Stratix 5800 <= 16.12.01 Rockwell Automation Stratix 8000 <= 15.2(7)E3
affected: vendor fix, mitigation “Rockwell Automation encourages users of the affected Stratix devices to update to an available firmware revision that addresses the associated risk.” rockwellautomation.custhelp.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-11-08)

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H
NVD	3.1	7.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H
NVD	2.0	7.1	AV:N/AC:M/Au:N/C:N/I:N/A:C

Affected products

Cisco Cisco IOS XE Software

Classification

Weakness

CWE-345 Insufficient Verification of Data Authenticity
CWE-1021 Improper Restriction of Rendered UI Layers or Frames

Technology feeds

Cisco IOS rss critical rss

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-cswsh-FKk9AzT5
vendor-advisory

Sources

CVE List CVE-2021-1403
NVD CVE-2021-1403

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary