# CVE-2026-8655 — NetScaler ADC

> As of 2026-06-30, CVE-2026-8655 is a CRITICAL-severity vulnerability in NetScaler ADC, CVSS v3.1 9.8, EPSS 0.4% (36.6th percentile). Threadlinqs Intelligence links 3 tracked threat campaigns to CVE-2026-8655, most recently “CitrixBleed-Class NetScaler ADC/Gateway SAML AuthnRequest Memory Disclosure (CVE-2026-8451) Exploited Within 24 Hours of Disclosure”.

**Last updated:** 2026-06-30

## What is CVE-2026-8655?

Multiple Memory overflow vulnerabilities in NetScaler ADC and NetScaler Gateway leading to unpredictable or erroneous behavior and Denial of Service if NetScaler ADC is configured as an LB of type Oracle OR NetScaler ADC is configured as a DNS Proxy OR NetScaler ADC is configured as a DNS recursive resolver deployment

The record classifies CVE-2026-8655 under weakness class [CWE-119](https://cwe.mitre.org/data/definitions/119.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 75 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 9.8 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **CVSS v4.0 base score:** 8.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:L`)
- **EPSS (FIRST):** 0.4% probability of exploitation in the next 30 days, higher than 36.6% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 6.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-06-30

## Is CVE-2026-8655 being exploited?

No public exploitation evidence for CVE-2026-8655 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-06-30. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.

## Affected products and versions

- **NetScaler**: ADC, Gateway

## How to fix CVE-2026-8655

Vendor advisory: [https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696604](https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696604). Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

## Threat activity tracking CVE-2026-8655

3 tracked threats in the Threadlinqs corpus reference CVE-2026-8655, either in the campaign’s CVE list or as an indicator on the campaign record.

- [CitrixBleed-Class NetScaler ADC/Gateway SAML AuthnRequest Memory Disclosure (CVE-2026-8451) Exploited Within 24 Hours of Disclosure](https://intel.threadlinqs.com/threat/TL-2026-1078) — CRITICAL · 2026-07-02
- [CVE-2026-8451: Memory Overread in Citrix NetScaler ADC/Gateway SAML IdP ('CitrixBleed'-class, CVSS 8.8) — Exploited Within 24 Hours of Disclosure](https://intel.threadlinqs.com/threat/TL-2026-1092) — HIGH · 2026-07-02
- [CitrixBleed 2.0: CVE-2026-8451 NetScaler SAML IDP Memory Overread Under Active Exploitation](https://intel.threadlinqs.com/threat/TL-2026-1140) — CRITICAL · 2026-06-30

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-07-02. This product uses the NVD API but is not endorsed or certified by the NVD.

**Other references**

- [support.citrix.com](https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696604)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-8655
Full detection coverage and IOCs for threats exploiting CVE-2026-8655 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp