CVE-2023-3519: Citrix NetScaler ADC and NetScaler Gateway Code Injection Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 19 Jul 2023, the same day the CVE record was published.

How likely is exploitation in the next 30 days?

99.7%

EPSS score, percentile 100 of all scored records

How severe?

9.8 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

Required action (CISA), due 9 Aug 2023: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected: 13.1 up to, not including, 49.13; 13.0 up to, not including, 91.13; 13.1-FIPS up to, not including, 37.159; 12.1-FIPS up to, not including, 55.297; 12.1-NDcPP up to, not including, 55.297; 13.1 up to, not including, 49.13; 13.0 up to, not including, 91.13

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 9 August 2023.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://support.citrix.com/article/CTX561482/citrix-adc-and-citrix-gateway-security-bulletin-for-cve20233519-cve20233466-cve20233467
• https://nvd.nist.gov/vuln/detail/CVE-2023-3519

Affected products and versions

As listed in the CVE record.

Versions not listed are: unaffected.

Versions not listed are: unaffected.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Citrix NetScaler ADC and NetScaler Gateway contains a code injection vulnerability that allows for unauthenticated remote code execution.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2023-3519 to its Known Exploited Vulnerabilities (KEV) catalog on 19 Jul 2023.
• CISA marks it as known to be used in ransomware campaigns.
• The due date CISA sets for the required action is 9 Aug 2023.
• The CVE record was published on 19 Jul 2023, the same day it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 99.7% (percentile 100), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

Unauthenticated remote code execution

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-94: Improper Control of Generation of Code ('Code Injection')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

References

• support.citrix.com
• packetstormsecurity.com

More exploited Citrix vulnerabilities

• CVE-2026-88779: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability (added 4 Oct 2026)
• CVE-2026-88771: Citrix NetScaler Improper Input Validation Vulnerability (added 27 Sep 2026)
• CVE-2026-88772: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability (added 27 Sep 2026)
• CVE-2026-19490: Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability (added 9 Sep 2026)
• CVE-2026-8452: Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability (added 26 Aug 2026)
• CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability (added 30 Mar 2026)