Exploited CVEs / Citrix / CVE-2026-88771

CVE-2026-88771

Citrix NetScaler Improper Input Validation Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-09-30 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Citrix Security Bulletins, linked below.

Our data comes from Microsoft, CISA and other public sources, and it can be wrong or out of date. If you are unsure, check the linked source before you act, and tell us when we are wrong so we can fix it.

CISA required actionOfficial fix for CVE-2026-88771What the press saysAdmin questions

Risk summary

CriticalCISA KEV
9.8
CVSS v3 base
9.5
CVSS v4
1.1%
EPSS exploit probability
Critical
Severity
2026-09-27
Added to KEV
2026-09-30 (past due)
CISA due date

Actively exploited Citrix NetScaler vulnerability, Critical severity, CVSS v3 9.8 (CVSS v4: 9.5). Added to the CISA KEV catalog 2026-09-27.

Patch now
Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.
The fix ships from the vendor: Citrix Security Bulletins.
Do this now: Federal remediation deadline 2026-09-30; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated September 29, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Senserva AI Opinion and rich prompt for CVE-2026-88771

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

Full tracking and change history for CVE-2026-88771

Published
2026-09-27
Last revised
2026-09-29
Changes tracked
1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one
What changed, and when

CISA confirmed active exploitation of CVE-2026-88771 on 2026-09-27.

0%25%50%75%100%CISA KEVCISA KEV on 2026-09-272026-09-29: EPSS 1.1%2026-09-29: EPSS 1.1%2026-10-05: EPSS 1.1%2026-10-05: EPSS 1.1%EPSS 1.1%2026-09-272026-10-05

Drawn by Senserva Vivid from the Senserva change record. Hover any point for its date and value.

  • 2026-09-27 added to the CISA KEV catalog by CISA
  • 2026-09-29 EPSS first scored at 1.1%
  • 2026-10-05 EPSS 1.1% to 1.1%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal remediation due date: 2026-09-30 (past due).

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.

Official fix for CVE-2026-88771

Update Citrix Netscaler Application Delivery Controller to version 13.1-64.23 or later. Update Citrix Netscaler Application Delivery Controller to version 13.1.37.279 or later. Update Citrix Netscaler Application Delivery Controller to version 14.1-73.37 or later. (Fixed-version data from NVD.)

Vendor advisoryCitrix Security BulletinsCISA KEV entry

Common questions about CVE-2026-88771

Is CVE-2026-88771 actively exploited?

Yes. CVE-2026-88771 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-09-27, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 1.1%.

What is the CISA deadline and required action for CVE-2026-88771?

CISA set the federal remediation due date at 2026-09-30, which has passed; treat any unremediated system as overdue. The verbatim 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.

What fixes CVE-2026-88771?

The authoritative fix is in the vendor advisory: see Citrix Security Bulletins for the patched NetScaler versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2026-88771?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-88771's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed daily (early morning US Central).

Scope and sources

More exploited Citrix CVEs
CVE-2026-88779CVE-2026-88772CVE-2026-19490CVE-2026-8452CVE-2026-3055CVE-2025-7775CVE-2024-8069CVE-2024-8068

All Citrix exploited CVEs on one page: Citrix vulnerabilities actively exploited.

Authoritative references
CVE recordNVD detailCISA KEV catalogFIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
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