Full Report
AL26-016 - Vulnerability impacting Citrix NetScaler CVE-2026-8451
Analysis Summary
# Vulnerability: Citrix NetScaler Memory Overread in SAML Identity Provider
## CVE Details
- **CVE ID:** CVE-2026-8451
- **CVSS Score:** Not explicitly listed in the article (Typically High for NetScaler memory overreads)
- **CWE:** CWE-125 (Out-of-bounds Read)
## Affected Systems
- **Products:** NetScaler ADC (formerly Citrix ADC), NetScaler Gateway (formerly Citrix Gateway), NetScaler ADC FIPS, and NFcPP/NDcPP appliances.
- **Versions:**
- NetScaler ADC and Gateway 14.1: Versions prior to 14.1-72.61
- NetScaler ADC and Gateway 13.1: Versions prior to 13.1-63.18
- NetScaler ADC FIPS: Versions prior to 14.1-72.61 FIPS
- NetScaler ADC FIPS and NDcPP: Versions prior to 13.1-37.272
- **Configurations:** Customer-managed instances configured as a **SAML Identity Provider (IdP)**. Cloud-managed Citrix services are not affected.
## Vulnerability Description
The vulnerability stems from insufficient input validation when processing SAML requests. This flaw allows an attacker to trigger an out-of-bounds read (CWE-125), resulting in a memory overread. This can lead to the disclosure of sensitive information residing in the system's memory.
## Exploitation
- **Status:** Not explicitly stated as exploited in the wild (based on the provided text), but listed as a current threat alert (AL26-016).
- **Complexity:** Not specified (Typically Low to Medium for input validation flaws).
- **Attack Vector:** Network (Remote).
## Impact
- **Confidentiality:** High (Memory overread can expose sensitive data, session tokens, or keys).
- **Integrity:** None/Minimal directly from this CVE.
- **Availability:** Low to Medium (Depending on if the read triggers a system crash).
## Remediation
### Patches
Organizations should upgrade to the following fixed versions:
- **NetScaler ADC / Gateway 14.1:** 14.1-72.61
- **NetScaler ADC / Gateway 13.1:** 13.1-63.18
- **NetScaler ADC FIPS:** 14.1-72.61
- **NetScaler ADC FIPS and NDcPP:** 13.1-37.272
### Workarounds
The article does not provide specific configuration workarounds; however, standard mitigation involves:
- Disabling SAML IdP functionality if not required.
- Isolating web-facing applications.
- Hardening the operating system.
## Detection
- **Indicators of Compromise:** Review Citrix guidance for systems suspected of compromise.
- **Detection methods and tools:** Monitor logs for anomalous SAML requests and follow instructions in Citrix KB article CTX694799.
## References
- **Vendor Advisory:** hxxps://support[.]citrix[.]com/support-home/kbsearch/article?articleNumber=CTX696604
- **Security Update Blog:** hxxps://community[.]citrix[.]com/techzone-blogs/110_security-updates/security-update-for-citrix-netscaler-and-netscaler-gateway-customers-r1570/
- **Canadian Centre for Cyber Security Alert:** hxxps://www[.]cyber[.]gc[.]ca/en/alerts-advisories/al26-016-vulnerability-impacting-citrix-netscaler-cve-2026-8451
- **NVD Detail:** hxxps://nvd[.]nist[.]gov/vuln/detail/CVE-2026-8451