CVE-2026-3055
Citrix NetScaler Out-of-Bounds Read Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 2 April 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread
- CVSS 4.0
- 9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 87.17% probability · 100th percentile
- CISA KEV
- Listed 30 March 2026 · due 2 April 2026
- Weakness
- CWE-125
- Affected
- citrix/netscaler application delivery controller · citrix/netscaler gateway
- Source
- 50a63c94-1ea7-4568-8c11-eb79e7c5a2b5
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300&articleURL=NetScaler_ADC_and_NetScaler_Gateway_Security_Bulletin_for_CVE_2026_3055_and_CVE_2026_4368 ; https://nvd.nist.gov/vuln/detail/CVE-2026-3055
References
- https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300Vendor Advisory
- https://labs.watchtowr.com/please-we-beg-just-one-weekend-free-of-appliances-citrix-netscaler-cve-2026-3055-memory-overread-part-2/Exploit, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-3055US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.