CVE-2026-88771: Citrix NetScaler Improper Input Validation Vulnerability
Citrix · NetScaler
Listed by CISA as exploited in the wild since 27 Sep 2026. Below: exploitation status, EPSS and every published CVSS, each with its source, then affected versions and references.
Build snapshot collected · KEV catalog 2026.10.02 · EPSS of 2 Oct 2026 · not a live feed: collected once, at build time
Description
as written by CISA (KEV catalog)
Citrix NetScaler ADC and NetScaler Gateway contain an improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands.
Required action
CISA KEV
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 and versions
CVE record · NetScaler
Citrix NetScaler · ADC
- affected: before 14.1-73.37
- affected: before 13.1-64.23
- affected: before 14.1-73.37 FIPS
- affected: before 13.1.37.279 FIPS and NDcPP
Citrix NetScaler · Gateway
- affected: before 14.1-73.37
- affected: before 13.1-64.23
Status words (affected, unaffected, unknown) and version bounds are copied from the record. An upper bound such as “before 7.1.0” usually marks the first fixed version; confirm in the vendor advisory before planning an upgrade.
References
CISA KEV notes and CVE record
- https://community.citrix.com/techzone-blogs/110_security-updates/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve-2026-88771-through-cve-2026-88778
- https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096
- https://support.citrix.com/external/article/CTX694799/steps-to-take-if-netscaler-adc-is-suspec.html
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-88772
EPSS over the last 30 days
See also: all Citrix entries in KEV · the full KEV catalog
Related entries
Other Citrix entries in KEV
- CVE-2026-88772Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-19490Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
- CVE-2026-8452Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-3055Citrix NetScaler Out-of-Bounds Read Vulnerability
- CVE-2025-7775Citrix NetScaler Memory Overflow Vulnerability
- CVE-2024-8069Citrix Session Recording Deserialization of Untrusted Data Vulnerability
Added in the same week (see the week)
- CVE-2026-67279Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability
- CVE-2026-65660Microsoft SharePoint Code Injection Vulnerability
- CVE-2026-87902WordPress Core Remote File Inclusion Vulnerability
- CVE-2026-5430WSO2 Multiple Products Path Traversal Vulnerability
- CVE-2026-71362Adobe Commerce and Magento Incorrect Authorization Vulnerability
- CVE-2026-93952Arista VeloCloud Orchestrator Improper Input Validation Vulnerability
Questions about CVE-2026-88771
Is CVE-2026-88771 being exploited?
Yes, according to CISA. CVE-2026-88771 was added to the Known Exploited Vulnerabilities catalog on 27 Sep 2026, which CISA does only with reliable evidence of exploitation in the wild. The catalog field for ransomware campaign use says "Unknown".
What is the deadline to remediate CVE-2026-88771?
CISA set 30 Sep 2026 as the due date for US Federal Civilian Executive Branch agencies. The date is binding only for those agencies; other organisations can read it as a measure of urgency.
What is the EPSS score of CVE-2026-88771?
1.06%, in the 63th percentile, in the FIRST EPSS model of 2 Oct 2026. It estimates the probability of exploitation activity in the following 30 days. For a CVE already in KEV the score is secondary: exploitation has been observed.
How severe is CVE-2026-88771?
NVD rates it 9.8 CRITICAL (CVSS 3.1); 50a63c94-1ea7-4568-8c11-eb79e7c5a2b5 rates it 9.5 CRITICAL (CVSS 4.0). These are the published assessments as of 3 Oct 2026; this site does not rescore.
Which product does CVE-2026-88771 affect?
Citrix NetScaler, as named in the CISA catalog. The affected versions listed in the CVE record are on this page; the vendor advisory in the references is the authority on fixed versions.
Related sections
- WatchlistWhat attackers started using this month, most urgent first.
- Exploited catalogEvery flaw CISA lists as used in real attacks (KEV), searchable.
- CVE lookupType one identifier: attack status, probability, severity, versions.
- Attack probabilityEPSS score for up to 100 identifiers at once.
- VendorsWhich vendors have the most exploited flaws.
- RSS and JSON feedsFollow new exploited flaws for the vendors you run.
- Sources and methodWhere each number comes from and how the order is decided.