Citrix NetScaler ADC/Gateway Unauthenticated RCE via Input Validation Flaw
Citrix NetScaler ADC and Gateway improper input validation flaw allows unauthenticated remote code execution; actively exploited and CISA KEV listed.
- Vendor
- Citrix
- Product
- NetScaler ADC, NetScaler Gateway
- CVSS
- N/A
- EPSS (exploit probability)
- 81.9%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Published
Is CVE-2026-88771 being exploited?
Yes. CISA added CVE-2026-88771 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild. It is also listed in ENISA's EU Vulnerability Database (EUVD) exploited list and CIRCL's KEV catalog.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 81.9% (scored November 5, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ LISTED ]
- CIRCL KEV[ LISTED ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2026-88771 timeline
- Added to CISA KEVsame day as NVD
- Added to EU KEV (ENISA)same day as NVD
- Published to NVD
- First 0dayNews coverage+1d
- Added to CIRCL KEV+1d
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
US federal civilian agencies must remediate by (3 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
CVE-2026-88771 is an improper input validation vulnerability in Citrix NetScaler ADC and NetScaler Gateway. An unauthenticated attacker can exploit it to execute arbitrary commands remotely.
The flaw was exploited in the wild before Citrix had assigned CVE IDs or released patches. CISA added it to the Known Exploited Vulnerabilities catalog on September 27, 2026, with a federal patching deadline of September 30, 2026. Citrix confirmed the CVE ID and released patches on September 28, 2026.
What to do: Apply the Citrix-supplied patches immediately. Check the Citrix security advisory for specific patched build versions. Before patching, review appliance logs for signs of prior compromise: unusual administrative sessions, unexpected configuration changes, and any web shell indicators. See the NVD record and CISA KEV catalog for further details.
Other Citrix NetScaler ADC and NetScaler Gateway CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2026-107406 Memory overflow in Citrix NetScaler ADC and Gateway SAML handlingwrite-up | [ CRITICAL ] | 9.5 | 1.9% | — |
| CVE-2026-88779 Citrix NetScaler Memory Buffer Flaw Enables Denial-of-Service Attackswrite-up | [ HIGH ] | 7.5 | 11.4% | |
| CVE-2026-88772 Citrix NetScaler ADC/Gateway RCE via Memory Buffer Mishandlingwrite-up | [ HIGH ] | — | 76.6% | |
| CVE-2026-19490 Critical authentication bypass in Citrix NetScaler ADC and Gatewaywrite-up | [ CRITICAL ] | 9.3 | 33.3% | |
| CVE-2026-8452 Citrix NetScaler ADC and Gateway Memory Buffer Overflowwrite-up | [ CRITICAL ] | 9.8 | 1.0% | |
| CVE-2025-5777 Citrix Bleed 2 — NetScaler ADC/Gateway memory-disclosure leaking session tokensransomware usewrite-up | [ HIGH ] | 7.5 | 100.0% | |
| CVE-2025-6543 Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability | [ CRITICAL ] | 9.8 | 10.4% | |
| CVE-2023-6549 Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability | [ HIGH ] | 8.2 | 57.6% |
