CVE-2026-88772: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 27 Sep 2026, the same day the CVE record was published.
- How likely is exploitation in the next 30 days?
- 78.2%
EPSS score, percentile 99.6 of all scored records
- How severe?
- 9.5 Critical
CVSS v4.0 base score, given by the CNA
- What should I do?
Required action (CISA), due 30 Sep 2026: 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.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected: before 14.1-73.37; before 13.1-64.23; before 14.1-73.37 FIPS; before 13.1.37.279 FIPS and NDcPP; before 14.1-73.37; before 13.1-64.23
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by 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.
CISA due date for this action: 30 September 2026.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- 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
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| 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 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 14.1-73.37 |
| Affected | before 13.1-64.23 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
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
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2026-88772 to its Known Exploited Vulnerabilities (KEV) catalog on 27 Sep 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 30 Sep 2026.
- The CVE record was published on 27 Sep 2026, the same day it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 9.5 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 78.2% (percentile 99.6), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
Memory overflow vulnerability leading to Remote Code Execution or Denial of Service
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 Remote Code Execution or Denial of Service
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 27 Sep 2026 | CVE record published |
| 27 Sep 2026 | Added to CISA KEV |
| 28 Sep 2026 | CVE record last updated |
| 30 Sep 2026 | CISA due date for the required action |
References
More exploited Citrix vulnerabilities
- CVE-2026-88779: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-88771: Citrix NetScaler Improper Input Validation Vulnerability
- CVE-2026-19490: Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
- CVE-2026-8452: Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability
- CVE-2025-7775: Citrix NetScaler Memory Overflow Vulnerability