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📋 Overview

CVE-2026-3055 is a critical out-of-bounds read vulnerability (CWE-125) in Citrix NetScaler ADC and NetScaler Gateway.

It is caused by insufficient input validation during SAML processing. An unauthenticated remote attacker can trigger a memory overread, leaking sensitive data from the appliance’s memory — including active session tokens, credentials, or other secrets under certain conditions.

This is the latest in the “CitrixBleed” family of memory disclosure issues.

Key Condition: The appliance must be explicitly configured as a SAML Identity Provider (IdP). Default configurations and non-SAML IdP setups are not affected.

Active reconnaissance against this vulnerability has already been observed in the wild.

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🔍 Technical Details

• CVE ID: CVE-2026-3055
• Citrix Advisory: CTX696300
• Severity: Critical
• CVSS v4.0 Score: 9.3 (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L)
• Vulnerability Type: Out-of-Bounds Read (Memory Overread) due to insufficient input validation
• Affected Component: SAML Identity Provider (IdP) processing logic
• Attack Vector: Remote, unauthenticated HTTP/S requests to SAML endpoints
• Authentication Required: None
• User Interaction: None
• Impact: Leakage of sensitive memory contents (session tokens, cookies, potential credentials or keys)
• Discovered By: Internally by Citrix security team
• Exploitation Status:
  • No public Proof-of-Concept (PoC) released yet
  • No confirmed in-the-wild exploitation (as of March 29, 2026)
  • Active reconnaissance/scanning ongoing

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📊 Affected Versions

• Not affected: Citrix-managed cloud instances
• Not affected: Appliances without SAML IdP configuration

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🛠️ How Attackers Exploit This Vulnerability

Exploitation Flow (High-Level):

1. Reconnaissance
   Attackers scan for exposed NetScaler appliances and check for SAML IdP configuration (often by sending test requests to SAML endpoints or looking for specific response patterns).

2. Trigger the Bug
   The attacker sends a specially crafted SAML-related request (typically to the SAML IdP endpoint) with malformed or oversized input that bypasses length/format validation.

3. Memory Overread
   Due to insufficient bounds checking, the appliance reads beyond the intended buffer and includes adjacent memory contents in the response.

4. Data Leak
   The leaked memory may contain:

   • Active session tokens / cookies
   • User credentials or session data
   • Other sensitive in-memory information

5. Post-Exploitation
   With stolen session tokens, attackers can hijack active sessions, bypass MFA, or move laterally without needing credentials.

Requirements for Successful Exploitation:

• The target must be configured as SAML Identity Provider (add authentication samlIdPProfile)
• Network reachability to the SAML endpoint (commonly internet-facing)
• No authentication needed — fully unauthenticated

Note: As of now, no public exploit code exists. However, once a PoC is released (or the patch is reverse-engineered), exploitation is expected to be straightforward and automated, similar to previous CitrixBleed vulnerabilities.

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✅ Remediation

Immediate Action Recommended:

1. Upgrade to a fixed build:
   • 14.1 → 14.1-66.59 or later
   • 13.1 → 13.1-62.23 or later
2. Check if vulnerable:
   root@kitploit:~

   show running-config | grep -i samlIdPProfile
   

   or look for the command: add authentication samlIdPProfile
3. If you cannot patch immediately:
   • Temporarily disable SAML IdP functionality
   • Restrict access to SAML endpoints via firewall / WAF
4. Monitor logs for suspicious SAML requests.

Official Advisory:
CTX696300 – NetScaler ADC and Gateway Security Bulletin

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🛡️ Best Practices & Mitigation

• Patch urgently — memory leaks in NetScaler have a history of rapid weaponization.
• Limit exposure of management and SAML endpoints.
• Use network segmentation and strong WAF/IPS rules.
• Regularly audit SAML and authentication configurations.
• Enable detailed logging and monitor for anomalous responses.

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📚 References

• Citrix Official Security Bulletin (CTX696300)
• NVD – CVE-2026-3055
• Rapid7 Analysis
• Arctic Wolf Blog
• The Hacker News – Active Recon Observed

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This repository is for defensive security, awareness, and educational purposes only.
No exploit code is provided here.

⭐ Star this repo if it helped you stay secure!
Contributions, corrections, or new IOCs are welcome via Pull Requests.

Last Updated: March 29, 2026