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
- 91.49% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- 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
EPSS moved from 4.0% on 24 September 2026 to 91.5% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
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, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.