How severe is CVE-2025-20333?

CVE-2025-20333 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-20333 being actively exploited?

Yes. CVE-2025-20333 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-09-25, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2025-20333?

CVE-2025-20333 primarily affects Cisco Adaptive Security Appliance Software. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-20333?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2025-20333 have an EU (EUVD) identifier?

Yes. CVE-2025-20333 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31140. It is also flagged as exploited in the EUVD (since 2025-09-25).

When was CVE-2025-20333 published?

CVE-2025-20333 was published on 2025-09-25 and last updated on 2026-06-17.

CVE-2025-20333

CVE-2025-20333 is a critical-severity vulnerability in Cisco Adaptive Security Appliance Software with a CVSS 3.x base score of 9.9. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2025-09-25). The underlying weakness is classified as CWE-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 40% (98th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2025-09-25)
EU (EUVD) id: EUVD-2025-31140
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2025-09-25)
Weakness: CWE-120
Affected product: Cisco Adaptive Security Appliance Software
Published: 2025-09-25
Last modified: 2026-06-17

Description

A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of the affected device.

Frequently asked questions

What is CVE-2025-20333?: A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of the affected device.
How severe is CVE-2025-20333?: CVE-2025-20333 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-20333 being actively exploited?: Yes. CVE-2025-20333 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-09-25, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2025-20333?: CVE-2025-20333 primarily affects Cisco Adaptive Security Appliance Software. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-20333?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2025-20333 have an EU (EUVD) identifier?: Yes. CVE-2025-20333 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31140. It is also flagged as exploited in the EUVD (since 2025-09-25).
When was CVE-2025-20333 published?: CVE-2025-20333 was published on 2025-09-25 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense:7.6.0:*:*:*:*:*:*:*

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