CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 7 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 91.5%
EPSS score, percentile 99.8 of all scored records
- How severe?
- 9.3 Critical
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline . Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- from 14.1 to before 66.59
- from 13.1 to before 62.23
- from 13.1 FIPS and NDcPP to before 37.262
- from 14.1 to before 66.59
- from 13.1 to before 62.23
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300&articleURL=NetScaler_ADC_and_NetScaler_Gateway_Security_Bulletin_for_CVE_2026_3055_and_CVE_2026_4368
- https://nvd.nist.gov/vuln/detail/CVE-2026-3055
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | from 14.1 to before 66.59 |
| Affected | from 13.1 to before 62.23 |
| Affected | from 13.1 FIPS and NDcPP to before 37.262 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | from 14.1 to before 66.59 |
| Affected | from 13.1 to before 62.23 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
Citrix NetScaler ADC (formerly Citrix ADC), NetScaler Gateway (formerly Citrix Gateway) and NetScaler ADC FIPS and NDcPP contain an out-of-bounds reads vulnerability when configured as a SAML IDP leading to memory overread.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2026-3055 to its Known Exploited Vulnerabilities (KEV) catalog on 30 Mar 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 2 Apr 2026.
- The CVE record was published on 23 Mar 2026, 7 days before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 9.3 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 91.5% (percentile 99.8), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
Insufficient input validation leading to memory overread
Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-125: Out-of-bounds Read
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CVE record last updated | |
| 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-2026-88772: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer 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-2025-7775: Citrix NetScaler Memory Overflow Vulnerability