Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2025-20333

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software · 9.8.1

Watch CVE-2025-20333 Browse KEV feed
Severity
CVSS 9.9 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
70.7%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2025-20333 is a vulnerability affecting Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Secure Firewall.... A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.1.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software

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.

Cisco Affected
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
9.8.1 9.8.1.5 9.8.1.7 9.8.2 9.8.2.8 9.8.2.14 9.8.2.15 9.8.2.17 9.8.2.20 9.8.2.24 9.8.2.26 9.8.2.28 9.8.2.33 9.8.2.35 9.8.2.38 9.8.3.8 9.8.3.11 9.8.3.14 9.8.3.16 9.8.3.18 9.8.3.21 9.8.3 9.8.3.26 9.8.3.29 9.8.4 9.8.4.3 9.8.4.7 9.8.4.8 9.8.4.10 9.8.4.12 9.8.4.15 9.8.4.17 9.8.2.45 9.8.4.25 9.8.4.20 9.8.4.22 9.8.4.26 9.8.4.29 9.8.4.32 9.8.4.33 9.8.4.34 9.8.4.35 9.8.4.39 9.8.4.40 9.8.4.41 9.8.4.43 9.8.4.44 9.8.4.45 9.8.4.46 9.8.4.48 9.12.1 9.12.1.2 9.12.1.3 9.12.2 9.12.2.4 9.12.2.5 9.12.2.9 9.12.3 9.12.3.2 9.12.3.7 9.12.4 9.12.3.12 9.12.3.9 9.12.2.1 9.12.4.2 9.12.4.4 9.12.4.7 9.12.4.10 9.12.4.13 9.12.4.8 9.12.4.18 9.12.4.24 9.12.4.26 9.12.4.29 9.12.4.30 9.12.4.35 9.12.4.37 9.12.4.38 9.12.4.39 9.12.4.40 9.12.4.41 9.12.4.47 9.12.4.48 9.12.4.50 9.12.4.52 9.12.4.54 9.12.4.55 9.12.4.56 9.12.4.58 9.12.4.62 9.12.4.65 9.12.4.67 9.14.1 9.14.1.10 9.14.1.6 9.14.1.15 9.14.1.19 9.14.1.30 9.14.2 9.14.2.4 9.14.2.8 9.14.2.13 9.14.2.15 9.14.3 9.14.3.1 9.14.3.9 9.14.3.11 9.14.3.13 9.14.3.18 9.14.3.15 9.14.4 9.14.4.6 9.14.4.7 9.14.4.12 9.14.4.13 9.14.4.14 9.14.4.15 9.14.4.17 9.14.4.22 9.14.4.23 9.14.4.24 9.16.1 9.16.1.28 9.16.2 9.16.2.3 9.16.2.7 9.16.2.11 9.16.2.13 9.16.2.14 9.16.3 9.16.3.3 9.16.3.14 9.16.3.15 9.16.3.19 9.16.3.23 9.16.4 9.16.4.9 9.16.4.14 9.16.4.18 9.16.4.19 9.16.4.27 9.16.4.38 9.16.4.39 9.16.4.42 9.16.4.48 9.16.4.55 9.16.4.57 9.16.4.61 9.16.4.62 9.16.4.67 9.16.4.70 9.16.4.71 9.16.4.76 9.16.4.82 9.16.4.84 9.17.1 9.17.1.7 9.17.1.9 9.17.1.10 9.17.1.11 9.17.1.13 9.17.1.15 9.17.1.20 9.17.1.30 9.17.1.33 9.17.1.39 9.18.1 9.18.1.3 9.18.2 9.18.2.5 9.18.2.7 9.18.2.8 9.18.3 9.18.3.39 9.18.3.46 9.18.3.53 9.18.3.55 9.18.3.56 9.18.4 9.18.4.5 9.18.4.8 9.18.4.22 9.18.4.24 9.18.4.29 9.18.4.34 9.18.4.40 9.19.1 9.19.1.5 9.19.1.9 9.19.1.12 9.19.1.18 9.19.1.22 9.19.1.24 9.19.1.27 9.19.1.28 9.19.1.31 9.20.1 9.20.1.5 9.20.2 9.20.2.10 9.20.2.21 9.20.2.22 9.20.3 9.20.3.4 9.22.1.1 9.22.1.2
Cisco Affected
Cisco Secure Firewall Threat Defense (FTD) Software
6.2.3 6.2.3.1 6.2.3.2 6.2.3.3 6.2.3.4 6.2.3.5 6.2.3.6 6.2.3.7 6.2.3.8 6.2.3.10 6.2.3.11 6.2.3.9 6.2.3.12 6.2.3.13 6.2.3.14 6.2.3.15 6.2.3.16 6.2.3.17 6.2.3.18 6.6.0 6.6.0.1 6.6.1 6.6.3 6.6.4 6.6.5 6.6.5.1 6.6.5.2 6.6.7 6.6.7.1 6.6.7.2 6.4.0 6.4.0.1 6.4.0.3 6.4.0.2 6.4.0.4 6.4.0.5 6.4.0.6 6.4.0.7 6.4.0.8 6.4.0.9 6.4.0.10 6.4.0.11 6.4.0.12 6.4.0.13 6.4.0.14 6.4.0.15 6.4.0.16 6.4.0.17 6.4.0.18 7.0.0 7.0.0.1 7.0.1 7.0.1.1 7.0.2 7.0.2.1 7.0.3 7.0.4 7.0.5 7.0.6 7.0.6.1 7.0.6.2 7.0.6.3 7.0.7 7.0.8 7.1.0 7.1.0.1 7.1.0.2 7.1.0.3 7.2.0 7.2.0.1 7.2.1 7.2.2 7.2.3 7.2.4 7.2.4.1 7.2.5 7.2.5.1 7.2.6 7.2.7 7.2.5.2 7.2.8 7.2.8.1 7.3.0 7.3.1 7.3.1.1 7.3.1.2 7.4.0 7.4.1 7.4.1.1 7.4.2 7.4.2.1 7.4.2.2 7.4.2.3 7.6.0
Published
25 Sep 2025
Exploitation Reported
01 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
Low
User interaction
None

Tags

cisa edge

CVE References

  • CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2025-20333
  • cisco-sa-asaftd-webvpn-z5xP8EUB sec.cloudapps.cisco.com · CVE Record https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurity...

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CVE

Recorded 01 Jun 2026

A trusted third party reported exploitation.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CVE First 2026-06-01 10:41 UTC
CISA 2026-06-02 14:06 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.9 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS

70.7%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') CWE-120

Timeline

From disclosure to observed exploitation

  1. 14:06 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  2. 10:41 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  3. 16:12 UTC

    CVE published

    Vulnerability disclosed publicly

  4. 19:15 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2025-20333

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2025-20333",
  "confidence": "Confirmed",
  "cvss_score": 9.9,
  "cvss_estimated": false,
  "epss_score": 0.70651,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}