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Known Exploited Vulnerability
8.2
HIGH CVSS 3.1
CVE-2023-6549
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability - [Actively Exploited]
Description

Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service and Out-Of-Bounds Memory Read

INFO

Published Date :

Jan. 17, 2024, 9:15 p.m.

Last Modified :

Oct. 24, 2025, 1:42 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.

Description :

Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for a denial-of-service when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

Required Action :

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Notes :

https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549; https://nvd.nist.gov/vuln/detail/CVE-2023-6549

Affected Products

The following products are affected by CVE-2023-6549 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 Action
1 Citrix netscaler_application_delivery_controller
2 Citrix netscaler_gateway
: Total Affected Vendor : 1 | Products : 2
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 HIGH [email protected]
CVSS 3.1 HIGH [email protected]
Solution
This information is provided by the 3rd party feeds.
  • Upgrade to version 13.0-92.21, 13.1-51.15, 14.1-12.35, or later.
Public PoC/Exploit Available at Github

CVE-2023-6549 has a 4 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-2023-6549.

URL Resource
https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549 Vendor Advisory
https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549 Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-6549 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-2023-6549 is associated with the following CWEs:

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-2023-6549 weaknesses.

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-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-42: MIME Conversion MIME Conversion CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File 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-100: Overflow Buffers Overflow Buffers CAPEC-123: Buffer Manipulation Buffer Manipulation

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).

Profile Photo
aaditbhandaribarc/reports

None

Updated: 3 weeks, 3 days ago
0 stars 0 fork 0 watcher
Born at : Oct. 7, 2025, 6:10 a.m. This repo has been linked 15 different CVEs too.
Profile Photo
jake-44/Research

Research conducted involving security vulnerabilities, incidents, emerging technology, current events, and more.

Updated: 1 year, 11 months ago
0 stars 0 fork 0 watcher
Born at : Sept. 2, 2023, 1:31 p.m. This repo has been linked 11 different CVEs too.
Profile Photo
H4lo/awesome-IoT-security-article

Collect some iot-related security articles, including vulnerability analysis, security conferences and papers, etc.

iot-security

Updated: 3 months, 1 week ago
285 stars 29 fork 29 watcher
Born at : Dec. 6, 2022, 1:11 p.m. This repo has been linked 47 different CVEs too.
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Ostorlab/KEV

Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

cisa-kev vulnerability 0day cisa exploits

Updated: 3 weeks ago
588 stars 42 fork 42 watcher
Born at : April 19, 2022, 8:58 a.m. This repo has been linked 1290 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-2023-6549 vulnerability anywhere in the article.

  • Dark Reading
Citrix Patches Critical Vulns in NetScaler ADC and Gateway

Source: Vladimir Sotnichenko via Alamy Stock PhotoNEWS BRIEFCitrix has fixed a critical vulnerability, tracked as CVE-2025-5777, found within NetScaler ADC and NetScaler Gateway.The vulnerability, ass ... Read more

Published Date: Jun 23, 2025 (4 months, 1 week ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2023-6549 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Modified Analysis by [email protected]

    Oct. 24, 2025

    Action Type Old Value New Value
    Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-6549 Types: US Government Resource
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-6549
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Removed Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-6549
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-6549
  • Modified Analysis by [email protected]

    Jan. 27, 2025

    Action Type Old Value New Value
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549
  • Modified Analysis by [email protected]

    Jun. 10, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    May. 10, 2024

    Action Type Old Value New Value
    Changed Description Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service and Out-Of-Bounds Memory Read
  • Initial Analysis by [email protected]

    Jan. 24, 2024

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549 No Types Assigned https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549 Vendor Advisory
    Added CWE NIST CWE-119
    Added CPE Configuration OR *cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:* versions from (including) 12.1 up to (excluding) 12.1-55.302 *cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:* versions from (including) 12.1 up to (excluding) 12.1-55.302 *cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:* versions from (including) 13.0 up to (excluding) 13.0-92.21 *cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:* versions from (including) 13.1 up to (excluding) 13.1-37.176 *cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:* versions from (including) 13.1 up to (excluding) 13.1-51.15 *cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:* versions from (including) 14.1 up to (excluding) 14.1-12.35 *cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:* versions from (including) 13.0 up to (excluding) 13.0-92.21 *cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:* versions from (including) 13.1 up to (excluding) 13.1-51.15 *cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:* versions from (including) 14.1 up to (excluding) 14.1-12.35
  • CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725

    Jan. 19, 2024

    Action Type Old Value New Value
    Added Vulnerability Name Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
    Added Required Action Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
    Added Due Date 2024-02-07
    Added Date Added 2024-01-17
  • CVE Modified by [email protected]

    Jan. 18, 2024

    Action Type Old Value New Value
    Changed Description Denial of Service Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service
  • CVE Received by [email protected]

    Jan. 17, 2024

    Action Type Old Value New Value
    Added Description Denial of Service
    Added Reference Citrix Systems, Inc. https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549 [No types assigned]
    Added CWE Citrix Systems, Inc. CWE-119
    Added CVSS V3.1 Citrix Systems, Inc. AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 8.2
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

76.09 }} 1.39%

score

0.98868

percentile