How severe is CVE-2021-1271?

CVE-2021-1271 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-1271 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1271?

CVE-2021-1271 affects Cisco Web Security Virtual Appliance. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-1271?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-1271 published?

CVE-2021-1271 was published on 2021-01-20 and last updated on 2026-06-17.

CVE-2021-1271

CVE-2021-1271 is a medium-severity vulnerability in Cisco Web Security Virtual Appliance with a CVSS 3.x base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
CVSS v2: 3.5
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Cisco Web Security Virtual Appliance
Published: 2021-01-20
Last modified: 2026-06-17

Description

A vulnerability in the web-based management interface of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface of an affected device. The vulnerability exists because the web-based management interface does not properly validate user-supplied input. An attacker could exploit this vulnerability by inserting malicious data into a specific data field in an affected interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface.

Frequently asked questions

What is CVE-2021-1271?: A vulnerability in the web-based management interface of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface of an affected device. The vulnerability exists because the web-based management interface does not properly validate user-supplied input. An attacker could exploit this vulnerability by inserting malicious data into a specific data field in an affected interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface.
How severe is CVE-2021-1271?: CVE-2021-1271 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-1271 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1271?: CVE-2021-1271 affects Cisco Web Security Virtual Appliance. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-1271?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1271 published?: CVE-2021-1271 was published on 2021-01-20 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wsa-xss-RuB5WGqL

Affected products (1)

cpe:2.3:a:cisco:web_security_virtual_appliance:*:*:*:*:*:*:*:*

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