CVE-2025-20393

10.0

CRITICAL CVSS 3.1

Cisco Multiple Products Improper Input Validation Vulnerability - [Actively Exploited]

Description

A vulnerability in the Spam Quarantine feature of Cisco AsyncOS Software for Cisco Secure Email Gateway and Cisco Secure Email and Web Manager could allow an unauthenticated, remote attacker to execute arbitrary system commands on an affected device with root privileges. This vulnerability is due to insufficient validation of HTTP requests by the Spam Quarantine feature. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with root privileges.

INFO

Published Date :

Dec. 17, 2025, 5:15 p.m.

Last Modified :

Jan. 16, 2026, 2 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]

CISA Notification

CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Due Date: Dec 24, 2025

Alert Date: Dec 17, 2025 | 42 days ago

Description :

Cisco Secure Email Gateway, Secure Email, AsyncOS Software, and Web Manager appliances contains an improper input validation vulnerability that allows threat actors to execute arbitrary commands with root privileges on the underlying operating system of an affected appliance.

Required Action :

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Notes :

Please adhere to Cisco's guidelines to assess exposure and mitigate risks. Apply any final mitigations provided by the vendor as soon as they become available. For more information please see: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 ; https://nvd.nist.gov/vuln/detail/CVE-2025-20393

Affected Products

The following products are affected by CVE-2025-20393 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID	Vendor	Product
1	Cisco	secure_email_and_web_manager
2	Cisco	asyncos
3	Cisco	secure_email_gateway
4	Cisco	secure_email_gateway_virtual_appliance_c100v
5	Cisco	secure_email_gateway_virtual_appliance_c300v
6	Cisco	secure_email_gateway_virtual_appliance_c600v
7	Cisco	secure_email_gateway_c195
8	Cisco	secure_email_gateway_c395
9	Cisco	secure_email_gateway_c695
10	Cisco	secure_email_and_web_manager_virtual_appliance_m100v
11	Cisco	secure_email_and_web_manager_virtual_appliance_m300v
12	Cisco	secure_email_and_web_manager_virtual_appliance_m600v
13	Cisco	secure_email_and_web_manager_m170
14	Cisco	secure_email_and_web_manager_m190
15	Cisco	secure_email_and_web_manager_m195
16	Cisco	secure_email_and_web_manager_m380
17	Cisco	secure_email_and_web_manager_m390
18	Cisco	secure_email_and_web_manager_m390x
19	Cisco	secure_email_and_web_manager_m395
20	Cisco	secure_email_and_web_manager_m680
21	Cisco	secure_email_and_web_manager_m690
22	Cisco	secure_email_and_web_manager_m690x
23	Cisco	secure_email_and_web_manager_m695

: Total Affected Vendor : 1 | Products : 23

CVSS Scores

The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.

Score	Version	Severity	Vector	Exploitability Score	Impact Score	Source
	CVSS 3.1	CRITICAL				[email protected]

Solution

Stay updated on Cisco's investigation and apply patches when released.

Monitor Cisco for vulnerability updates.
Apply security patches when available.

Public PoC/Exploit Available at Github

CVE-2025-20393 has a 12 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-20393.

URL	Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4	Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20393	US Government Resource

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-20393 is associated with the following CWEs:

CWE-20: Improper Input Validation

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-20393 weaknesses.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client CAPEC-23: File Content Injection File Content Injection CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-31: Accessing/Intercepting/Modifying HTTP Cookies Accessing/Intercepting/Modifying HTTP Cookies CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-63: Cross-Site Scripting (XSS) Cross-Site Scripting (XSS) CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-73: User-Controlled Filename User-Controlled Filename CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-81: Web Server Logs Tampering Web Server Logs Tampering CAPEC-83: XPath Injection XPath Injection CAPEC-85: AJAX Footprinting AJAX Footprinting CAPEC-88: OS Command Injection OS Command Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-104: Cross Zone Scripting Cross Zone Scripting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-109: Object Relational Mapping Injection Object Relational Mapping Injection CAPEC-110: SQL Injection through SOAP Parameter Tampering SQL Injection through SOAP Parameter Tampering CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-136: LDAP Injection LDAP Injection CAPEC-153: Input Data Manipulation Input Data Manipulation CAPEC-182: Flash Injection Flash Injection CAPEC-209: XSS Using MIME Type Mismatch XSS Using MIME Type Mismatch CAPEC-230: Serialized Data with Nested Payloads Serialized Data with Nested Payloads CAPEC-231: Oversized Serialized Data Payloads Oversized Serialized Data Payloads CAPEC-250: XML Injection XML Injection CAPEC-261: Fuzzing for garnering other adjacent user/sensitive data Fuzzing for garnering other adjacent user/sensitive data CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-473: Signature Spoof Signature Spoof CAPEC-588: DOM-Based XSS DOM-Based XSS CAPEC-664: Server Side Request Forgery Server Side Request Forgery

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

cyberdudebivash/CYBERDUDEBIVASH-Cisco-AsyncOS-CVE-2025-20393-Scanner

This tool helps identify exposure to CVE-2025-20393 by checking for open TCP/6025 ports, responsive Spam Quarantine interfaces, and known post-exploitation IOCs.

Python

Updated: 1 week, 4 days ago

0 stars 0 fork 0 watcher

Born at : Jan. 16, 2026, 5:34 p.m. This repo has been linked 1 different CVEs too.

MRH701/mrh701.github.io

🔍 Probe hosts for open Cisco Secure Email/Malware Analytics ports and CVE-2025-20393 exposure using a simple Python script.

Updated: 2 weeks, 5 days ago

0 stars 0 fork 0 watcher

Born at : Jan. 6, 2026, 11:16 p.m. This repo has been linked 1 different CVEs too.

MRH701/cisco-sa-sma-attack-N9bf4

🔍 Probe Cisco Secure Email and Malware Analytics for open ports and vulnerabilities with this lightweight Python script.

aouth2 automation cisco configs cve-2025-20393 docker encryption firewall gtasa ipsec java libreswan mtasa qt raspberry-pi router security vpn vpn-client

Python

Updated: 1 week, 2 days ago

0 stars 0 fork 0 watcher

Born at : Jan. 6, 2026, 11:07 p.m. This repo has been linked 1 different CVEs too.

tralsesec/AnatomyOfABug

Full Breakdown of CVEs & more.

Updated: 1 month ago

0 stars 0 fork 0 watcher

Born at : Dec. 25, 2025, 8:17 a.m. This repo has been linked 9 different CVEs too.

Ashwesker/Blackash-CVE-2025-20393

CVE-2025-20393

Python

Updated: 1 month, 1 week ago

0 stars 0 fork 0 watcher

Born at : Dec. 19, 2025, 1:26 p.m. This repo has been linked 1 different CVEs too.

StasonJatham/cisco-sa-sma-attack-N9bf4

Script to detect CVE-2025-20393 for Cisco Secure Email Gateway And Cisco Secure Email and Web Manager

cisco cve sma cve-2025-20393

Python

Updated: 1 month, 1 week ago

16 stars 1 fork 1 watcher

Born at : Dec. 18, 2025, 12:55 p.m. This repo has been linked 1 different CVEs too.

b1gchoi/CVE-2025-20393

None

Updated: 1 month, 1 week ago

0 stars 0 fork 0 watcher

Born at : Dec. 18, 2025, 12:29 p.m. This repo has been linked 1 different CVEs too.

KingHacker353/CVE-2025-20393

None

Updated: 1 month, 1 week ago

0 stars 0 fork 0 watcher

Born at : Dec. 18, 2025, 12:10 p.m. This repo has been linked 1 different CVEs too.

cyberleelawat/CVE-2025-20393

Cisco is aware of a potential vulnerability.  Cisco is currently investigating and will update these details as appropriate as more information becomes available.

Python

Updated: 1 month ago

2 stars 1 fork 1 watcher

Born at : Dec. 18, 2025, 10:02 a.m. This repo has been linked 1 different CVEs too.

thesystemowner/CVE-2025-20393-POC

This scanner detects Cisco SEG/SEWM appliances vulnerable to CVE-2025-20393, a critical unauthenticated RCE vulnerability in Cisco AsyncOS affecting devices with Spam Quarantine feature exposed to the internet. CVSS Score: 10.0 (Critical)

Python

Updated: 1 month, 1 week ago

1 stars 0 fork 0 watcher

Born at : Dec. 18, 2025, 7:25 a.m. This repo has been linked 1 different CVEs too.

DevGreick/devgreick

None

Python

Updated: 2 weeks, 4 days ago

1 stars 0 fork 0 watcher

Born at : Oct. 29, 2024, 8:10 p.m. This repo has been linked 11 different CVEs too.

nomi-sec/PoC-in-GitHub

📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.

security cve exploit poc vulnerability

Updated: 2 weeks, 4 days ago

7462 stars 1233 fork 1233 watcher

Born at : Dec. 8, 2019, 1:03 p.m. This repo has been linked 826 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-20393 vulnerability anywhere in the article.

The Hacker News

Cisco Fixes Actively Exploited Zero-Day CVE-2026-20045 in Unified CM and Webex

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Published Date: Jan 22, 2026 (5 days, 22 hours ago)

Help Net Security

Initial access broker pleads guilty to selling access to 50 corporate networks

A 40-year-old Jordanian man has admitted to selling unauthorized access to computer networks of at least 50 companies, the US Attorney’s Office of the District of New Jersey has announced. Feras Khali ...

Published Date: Jan 20, 2026 (1 week ago)

Help Net Security

Week in review: PoC for FortiSIEM flaw released, Rakuten Viber CISO/CTO on messaging risks

Here’s an overview of some of last week’s most interesting news, articles, interviews and videos: What security teams can learn from torrent metadata Security teams often spend time sorting through lo ...

Published Date: Jan 18, 2026 (1 week, 2 days ago)

TheCyberThrone

Mozilla fixes multiple Sandbox escape Bugs

January 17, 2026The most recent Mozilla Firefox sandbox escape vulnerabilities were disclosed in January 2026 as part of Firefox security updates. These critical flaws affect multiple components and r ...

Published Date: Jan 17, 2026 (1 week, 3 days ago)

Help Net Security

Cisco fixes AsyncOS vulnerability exploited in zero-day attacks (CVE-2025-20393)

Cisco has finally shipped security updates for its Email Security Gateway and Secure Email and Web Manager devices, which fix CVE-2025-20393, a vulnerability in the devices’ AsyncOS that has been expl ...