How severe is CVE-2021-1516?

CVE-2021-1516 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-1516 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1516?

CVE-2021-1516 primarily affects Cisco Content Security Management Appliance. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-1516?

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

When was CVE-2021-1516 published?

CVE-2021-1516 was published on 2021-05-06 and last updated on 2026-06-17.

CVE-2021-1516

CVE-2021-1516 is a medium-severity vulnerability in Cisco Content Security Management Appliance with a CVSS 3.x base score of 4.3. 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-540.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-540
Affected product: Cisco Content Security Management Appliance
Published: 2021-05-06
Last modified: 2026-06-17

Description

A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Content Security Management Appliance (SMA), Cisco Email Security Appliance (ESA), and Cisco Web Security Appliance (WSA) could allow an authenticated, remote attacker to access sensitive information on an affected device. The vulnerability exists because confidential information is included in HTTP requests that are exchanged between the user and the device. An attacker could exploit this vulnerability by looking at the raw HTTP requests that are sent to the interface. A successful exploit could allow the attacker to obtain some of the passwords that are configured throughout the interface.

Frequently asked questions

What is CVE-2021-1516?: A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Content Security Management Appliance (SMA), Cisco Email Security Appliance (ESA), and Cisco Web Security Appliance (WSA) could allow an authenticated, remote attacker to access sensitive information on an affected device. The vulnerability exists because confidential information is included in HTTP requests that are exchanged between the user and the device. An attacker could exploit this vulnerability by looking at the raw HTTP requests that are sent to the interface. A successful exploit could allow the attacker to obtain some of the passwords that are configured throughout the interface.
How severe is CVE-2021-1516?: CVE-2021-1516 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-1516 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1516?: CVE-2021-1516 primarily affects Cisco Content Security Management Appliance. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1516?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1516 published?: CVE-2021-1516 was published on 2021-05-06 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-wsa-sma-info-gY2AEz2H

Affected products (8)

cpe:2.3:a:cisco:content_security_management_appliance:-:*:*:*:*:*:*:*
cpe:2.3:a:cisco:email_security_appliance:-:*:*:*:*:*:*:*
cpe:2.3:a:cisco:web_security_appliance:-:*:*:*:*:*:*:*
cpe:2.3:a:cisco:ironport_web_security_appliance:13.6.2-023:*:*:*:*:*:*:*
cpe:2.3:a:cisco:ironport_web_security_appliance:14.0.0-090:*:*:*:*:*:*:*
cpe:2.3:a:cisco:ironport_web_security_appliance:14.0.0-133:*:*:*:*:*:*:*
cpe:2.3:a:cisco:ironport_web_security_appliance:14.0.0-292:*:*:*:*:*:*:*
cpe:2.3:a:cisco:ironport_web_security_appliance:14.0.0-300:*:*:*:*:*:*:*

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