CVEs / CVE-2026-3055
CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability
- Known exploited in the CISA KEV catalog since 30 Mar 2026
- critical 9.8 CVSS 3.1 (NVD)
- EPSS 91.4% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
Description
Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| NetScaler ADC | from 14.1, before 66.59 | 66.59 |
| NetScaler ADC | from 13.1, before 62.23 | 62.23 |
| NetScaler ADC | from 13.1 FIPS and NDcPP, before 37.262 | 37.262 |
| NetScaler Gateway | from 14.1, before 66.59 | 66.59 |
| NetScaler Gateway | from 13.1, before 62.23 | 62.23 |
Exploitation
| In CISA KEV since | 30 Mar 2026 |
|---|---|
| Due date for US federal agencies | 2 Apr 2026 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-125 |
References
- CVE-2026-3055 on NVD
- CVE-2026-3055 in the CISA KEV catalog
- 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 (cited by CISA)
- https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300 Vendor 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-2026-3055 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.