Citrix NetScaler Out-of-Bounds Read Vulnerability

[ Why it matters ]Priority signals

• Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-03-30
• Critical severity: CVSS 9.8

[ Description ]Official description

Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread

CISA: Citrix NetScaler ADC (formerly Citrix ADC), NetScaler Gateway (formerly Citrix Gateway) and NetScaler ADC FIPS and NDcPP contain an out-of-bounds reads vulnerability when configured as a SAML IDP leading to memory overread.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 2 Apr 2026): Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• support.citrix.com/support-home/kbsearch/articleVendor Advisory
• labs.watchtowr.com/please-we-beg-just-one-weekend-free-of-appliances-citrix-netscaler-c…ExploitThird Party Advisory
• www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource