CVE-2026-3055
Published: 23 March 2026
Summary
CVE-2026-3055 is a critical-severity Out-of-bounds Read (CWE-125) vulnerability in Citrix Netscaler Application Delivery Controller. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-3055 is an out-of-bounds memory read (CWE-125) caused by insufficient input validation in Citrix NetScaler ADC and NetScaler Gateway when those appliances are configured as SAML identity providers. The flaw carries a CVSS 4.0 score of 9.3 and affects the SAML assertion handling path, allowing an unauthenticated remote attacker to read memory contents beyond intended boundaries.
An attacker who can reach the SAML IDP endpoint can supply a crafted request that triggers the overread. Successful exploitation yields disclosure of sensitive memory regions, which may contain session tokens, cryptographic material, or other data that can be leveraged to escalate to full compromise of the affected appliance.
Citrix security bulletin CTX696300 describes the affected versions and provides patched builds; administrators are advised to apply the vendor updates or implement the recommended configuration mitigations. The vulnerability is also listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild.
The EPSS score has remained at its observed peak of 0.8992 since disclosure, indicating sustained exploitation interest.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-14546
- 🇬🇧 UK NCSC: Vulnerabilities affecting Citrix NetScaler ADC and Citrix NetScaler Gateway
Vulnerability details
Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread
- CWE(s)
- KEV Date Added
- 30 March 2026
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability is a remotely exploitable flaw in a public-facing NetScaler ADC/Gateway SAML IDP with no privileges required, directly enabling T1190: Exploit Public-Facing Application.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation of all inputs to the SAML IDP assertion handler, eliminating the malformed request that triggers the out-of-bounds memory read.
Enforces memory-access protections that block or contain the out-of-bounds read in the SAML processing path before sensitive data can be disclosed.
Mandates prompt installation of the vendor patches listed in CTX696300, removing the insufficient-validation flaw from the affected NetScaler builds.