How severe is CVE-2024-20256?

CVE-2024-20256 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-2024-20256 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-20256?

CVE-2024-20256 primarily affects Cisco Asyncos. In total, 51 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-20256?

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

Does CVE-2024-20256 have an EU (EUVD) identifier?

Yes. CVE-2024-20256 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-17971.

When was CVE-2024-20256 published?

CVE-2024-20256 was published on 2024-05-15 and last updated on 2026-06-17.

CVE-2024-20256

CVE-2024-20256 is a medium-severity vulnerability in Cisco Asyncos 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)
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-17971
Weakness: CWE-79
Affected product: Cisco Asyncos
Published: 2024-05-15
Last modified: 2026-06-17

Description

A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Secure Email and Web Manager and Secure Web Appliance could allow an authenticated, remote attacker to conduct an XSS attack against a user of the interface. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user of an affected interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.

Frequently asked questions

What is CVE-2024-20256?: A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Secure Email and Web Manager and Secure Web Appliance could allow an authenticated, remote attacker to conduct an XSS attack against a user of the interface. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user of an affected interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.
How severe is CVE-2024-20256?: CVE-2024-20256 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-2024-20256 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-20256?: CVE-2024-20256 primarily affects Cisco Asyncos. In total, 51 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-20256?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-20256 have an EU (EUVD) identifier?: Yes. CVE-2024-20256 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-17971.
When was CVE-2024-20256 published?: CVE-2024-20256 was published on 2024-05-15 and last updated on 2026-06-17.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-sma-wsa-xss-bgG5WHOD

Affected products (51)

cpe:2.3:o:cisco:asyncos:11.7.0-406:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.7.0-418:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.7.1-006:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.7.1-020:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.7.1-049:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.7.2-011:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.8.0-414:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.8.1-023:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.8.3-018:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.8.3-021:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.0.1-268:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.0.3-007:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.1-011:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.2-007:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.4-005:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.5-004:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.6-008:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:14.0.2-012:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:14.0.3-014:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:14.0.4-005:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:14.5.0-498:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:14.5.1-016:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:15.0.0-322:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_email_and_web_manager_virtual_appliance_m100v:-:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_email_and_web_manager_virtual_appliance_m300v:-:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_email_and_web_manager_virtual_appliance_m600v:-:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:9.0.0-087:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.0.0-115:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.0.1-161:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:11.5.1-105:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.0.0-452:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.0.1-011:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.0-636:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.0-658:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.0-670:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.5.0-678:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.8.1-002:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:12.8.1-021:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:13.0.0-277:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asyncos:13.6.2-078:*:*:*:*:*:*:*

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