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Response snapshot Oct 26, 2026, 21:58 UTC

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VulnerabilityCVE-2025-20333Known exploitation

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability

Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Software VPN Web Server contain a buffer overflow vulnerability that allows for remote code execution. This vulnerability could be chained with CVE-2025-20362.

At a glance

Exploited
Yes: on CISA's Known Exploited list
Severity
Not scored yet
Chance of exploitation
71.2% in the next 30 days
CISA federal deadline
Sep 26, 2025: passed
Sources
1 source

What to do

The KEV due date refers to the deadline by which FCEB agencies are expected to review and begin implementing the guidance outlined in Emergency Directive (ED) 25-03 (URL listed below in Notes). Agencies must follow the mitigation steps provided by CISA (URL listed below in Notes) and vendor’s instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

Read CISA KEV entry CVE-2025-20333 (opens a new tab)

CISA federal deadline

Federal due date passed

Applies to covered US federal agencies; it is not your organization's deadline.

Added to the catalog Known ransomware use: Unknown
CISA catalog (opens a new tab)

Scores and how they were measured

CVSS base severity

Not available

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

71.2%

Scored Percentile 99.4%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    CISA KEV entry CVE-2025-20333 (opens a new tab)

    The CVE-2025-20333 catalog entry establishes known exploitation, date added, required action, and the federal due date; not zero-day status.

    Published Checked

  2. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2025-20333, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2025, September 25). Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability (CVE-2025-20333). https://kevwire.com/record/CVE-2025-20333

MLA

"Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability (CVE-2025-20333)." KEVWire, 25 Sept. 2025, kevwire.com/record/CVE-2025-20333.

Chicago

KEVWire. "Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability (CVE-2025-20333)." Last modified September 25, 2025. https://kevwire.com/record/CVE-2025-20333.

Evidence summary (plain text)

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability (Sep 25, 2025).
Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Software VPN Web Server contain a buffer overflow vulnerability that allows for remote code execution. This vulnerability could be chained with CVE-2025-20362.
EPSS 71.2% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2025-20333&date=2026-10-26).
Sources:
CISA KEV entry CVE-2025-20333: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2025-20333&date=2026-10-26
Record ID: CVE-2025-20333.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Documented by a cited source.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
CISA federal due date: Sep 26, 2025. This is a deadline for covered US federal agencies, not the reader's SLA.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

CISA added this entry on 2025-09-25. This record's publication date is the catalog addition date, not necessarily the initial vulnerability disclosure. KEV means known exploitation, not necessarily a zero-day. CISA due dates apply to covered US federal agencies, not your organizational SLA.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail