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CVE-2025-20333

Buffer Overflow — is CVE-2025-20333real, exploitable, or a false positive? Here's the community ground truth.

Critical · CVSS 9.9EPSS 29.2%CISA KEVCWE-120 · Buffer Overflow

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

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.

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Community ground truth

Community verdict

3 verdicts
Not a real issue

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Community real-world severity: Critical (Critical 3) — CVSS base score 9.9

In line with its CVSS base score.

Field notes & remediation

Verdicts are the quick signal — notes are the evidence and fixes behind them.

  • 0
    Field note · Priya NairCurated

    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. Listed in the CISA KEV catalog (added 2025-09-25) — confirmed exploited in the wild, not theoretical. FIRST EPSS puts the chance of exploitation in the next 30 days at ~29%. Treat it as real and prioritize remediation over triage.

  • 0
    Remediation · Diego RamírezCurated

    Required action for Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense: 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. CISA set a federal remediation due date of 2025-09-26. After patching, verify the vulnerable path is no longer reachable before closing the finding.

Same weaknessCWE-120 · Buffer Overflow.