CVE-2026-88771
CriticalExploitedPublic exploitA remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands
Published Sep 27, 2026 · Updated Sep 29, 2026 · Also known as EUVD-2026-87958, GHSA-mx58-p288-86qp, TR-26-1326
Key Facts
Patch immediately- CVE-2026-88771 is a critical-severity vulnerability (CVSS 9.5 v4) affecting Netscaler Application Delivery Controller (Citrix), Netscaler Gateway (Citrix).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 27, 2026. Public exploit code is available.
- EPSS estimates a 1.1% probability of exploitation in the next 30 days.
- Fixed versions are available, including Netscaler Application Delivery Controller 13.1-64.23, Netscaler Application Delivery Controller 13.1.37.279 FIPS and NDcPP, Netscaler Application Delivery Controller 14.1-73.37.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v4
9.5
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
EPSS (30-day exploit likelihood)
1.1%
Higher than 64.6% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-88771 brief as a PDF
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Description
Improper input validation vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway.
This issue affects ADC: before 14.1-73.37, before 13.1-64.23, before 14.1-73.37 FIPS, and before 13.1.37.279 FIPS and NDcPP; Gateway: before 14.1-73.37 and before 13.1-64.23 leading to an unauthenticated attacker to execute arbitrary commands.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Sep 27, 2026 | Sep 30, 2026 | Not reported |
| Industry KEV feed | Sep 27, 2026 | Sep 30, 2026 | Not reported |
| CIRCL KEV | Sep 27, 2026 | Sep 30, 2026 | Not reported |
| ENISA EUVD | Sep 27, 2026 | n/a | Not reported |
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Affected Products
8 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Netscaler Application Delivery ControllerCitrix | See advisory | 13.1-64.23 |
| Netscaler GatewayCitrix | See advisory | 13.1-64.23 |
Patched Releases
Netscaler Application Delivery Controller
13.1-64.23, 13.1.37.279 FIPS and NDcPP, 14.1-73.37, 14.1-73.37 FIPS, 13.1.37.279
Netscaler Gateway
13.1-64.23, 14.1-73.37
Timeline
Publicly disclosed
Sep 27, 2026
Added to CISA KEV
Sep 27, 2026
Added to Industry KEV feed
Sep 27, 2026
Added to CIRCL KEV
Sep 27, 2026
Added to ENISA EUVD
Sep 27, 2026
Last updated
Sep 29, 2026
Weakness Type
- CWE-20 Improper Input Validation
References
- advisoryhttps://cert.europa.eu/publications/security-advisories/2026-014
- advisoryhttps://community.citrix.com/techzone-blogs/110_security-updates/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve-2026-88771-through-cve-2026-88778/
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-88771
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-88772
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-88773
FAQ
Common Questions.
Improper input validation vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway.
Affected: Netscaler Application Delivery Controller (Citrix); Netscaler Gateway (Citrix). The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 27, 2026.
Yes. It was added on Sep 27, 2026 with a federal remediation due date of Sep 30, 2026.
Public exploit code is available.
Fixed versions are available, including Netscaler Application Delivery Controller 13.1-64.23, Netscaler Application Delivery Controller 13.1.37.279 FIPS and NDcPP, Netscaler Application Delivery Controller 14.1-73.37.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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