~/exploited / cve-2026-88772

CVE-2026-88772: Citrix NetScaler

According to CISA this vulnerability is already used in attacks (added on 27 September 2026).

Key facts

CVE	CVE-2026-88772
Vendor	Citrix — NetScaler
Vulnerability	Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
Added	27 September 2026
Deadline (US agencies)	30 September 2026
Ransomware campaigns	unknown

Description (CISA)

Citrix NetScaler ADC and NetScaler Gateway contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for remote code execution or denial of service

Required action (CISA)

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 admins should do now

Affected? Check whether Citrix NetScaler is in use and which version runs (package manager, admin UI, --version).
Apply the vendor patch or workaround as soon as it exists. If that is not possible right away: restrict outside access (firewall, VPN, reverse proxy).
Review logs back to 27 September 2026: unusual logins, new files, unexpected processes, outbound connections.
If you suspect a compromise: isolate the system, rotate credentials, check the last backup from before the incident.

The deadline applies to US federal agencies. It is still a useful yardstick for everyone: when a flaw is attacked in the wild, waiting is not an option.

Sources

Data: CISA Known Exploited Vulnerabilities Catalog, as of 30 October 2026. No guarantee — always check the vendor's advisory.

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