NVD / CVE Program· CNA cisco

CVE-2025-20333: A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat…

CriticalCVSS 9.9 · v3.1KEVWeaponized No fix recorded

Noroxi assessment

Priority: Now (action score 91/100)

CISA has confirmed exploitation in the wild (Sep 25, 2025). Remediation deadline for US federal agencies: Sep 26, 2025.
Probability of exploitation in the next 30 days: 72% (FIRST EPSS); higher than 99.4% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Patch today or shut off access. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

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.

BDU:2025-11706

Published: Sep 25, 2025
Updated: Oct 18, 2026
EPSS: 72.0% · 99th percentile
CWE: CWE-120

Report tools

JSON

Action score

Now

Patch today or shut off access.

CVSS: 39 / 40 · 9.9 / 10
CISA KEV: 30 / 30 · Listed
EPSS: 22 / 30 · 72.0%

CISA SSVC decision

Exploitation: active
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · cisco: 9.9; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Sep 25, 2025. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Sep 26, 2025.

Get told when this record changes

In CISA KEV: exploitation in the wild confirmed
Weaponized exploit exists
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
cisco	adaptive security appliance software	cpe:2.3:o:cisco:adaptive_security_appliance_software
cisco	secure firewall threat defense	cpe:2.3:a:cisco:secure_firewall_threat_defense

Using adaptive security appliance software? Add it to your stack and be the first to know about CVEs like this one. (Firewall)

Versions reported by the vendor

Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.

Cisco 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 … (+28)affected
Cisco 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 … (+28)affected

Affected versions · NVD (12)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

cisco adaptive security appliance software9.12 and later · before 9.12.4.72
cisco adaptive security appliance software9.14 and later · before 9.14.4.28
cisco adaptive security appliance software9.16 and later · before 9.16.4.85
cisco adaptive security appliance software9.17.0 and later · before 9.17.1.45
cisco adaptive security appliance software9.18 and later · before 9.18.4.47
cisco adaptive security appliance software9.19 and later · before 9.19.1.37
cisco adaptive security appliance software9.20 and later · before 9.20.3.7
cisco adaptive security appliance software9.22 and later · before 9.22.1.3
cisco secure firewall threat defense7.0.0 and later · before 7.0.8.1
cisco secure firewall threat defense7.1.0 and later · before 7.2.9
cisco secure firewall threat defense7.3.0 and later · before 7.4.2.4
cisco secure firewall threat defense7.6.0

Same product

cisco: all records

Other highest-scoring records for the same primary product.

CVE-2025-20362Update: On November 5, 2025, Cisco became aware of a new attack variant against devices running Cisco Secure ASA Software or Cisco Secure…KEV
90Now
CVE-2020-3452Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Read-Only Path Traversal VulnerabilityKEV
90Now
CVE-2018-0296A vulnerability in the web interface of the Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to…KEV
90Now

Published before and after this one in the same product

← EarlierCVE-2020-27124Nov 18, 2024 · Cisco Adaptive Security Appliance Software SSL/TLS Denial of Service Vulnerability
34Monitor
← EarlierCVE-2025-20182May 7, 2025 · Cisco Adaptive Security Appliance Software, Firepower Threat Defense Software and IOS XE Software IKEv2 Denial of Service Vulnerability
34Monitor
Later →CVE-2026-20008Mar 4, 2026 · Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Lua Code Injection Vulnerability
24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Proof-of-concept repository on GitHub	3 repositories	2026-05-16 → 2026-08-31

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

CISA KEVSep 25, 2025-1 d
PublishedSep 25, 2025
First PoCMay 16, 2026+232 d
TodayNov 14, 2026+415 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-20100160 days apartA vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA)…
30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

CVE-2026-20009160 days apartCisco Secure Firewall Adaptive Security Appliance SSH Partial Private Key Authentication Bypass Vulnerability
21Monitor

Not on record for this CVE: patch commit or PR link · researcher credit · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Changed
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

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

CVSS vector

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

nvd-secondary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1char buf[256];
2memcpy(buf, pkt->data, pkt->len);

Fixed

1char buf[256];
2if (pkt->len > sizeof(buf)) {
3  return -EINVAL;
4}
5memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log (0)

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-webvpn-z5xP8EUB

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records