Threat Intelligence / CVE / CVE-2026-8451

CVE-2026-8451 — NetScaler ADC

CVSS v3.1 7.5 (HIGH) · CVSS v4.0 8.8 · EPSS 0.5% (higher than 39.2% of all scored CVEs) · Priority 7.3/10 · Published 2026-06-30

As of 2026-06-30, CVE-2026-8451 is a HIGH-severity vulnerability in NetScaler ADC, CVSS v3.1 7.5, EPSS 0.5% (39.2th percentile). Threadlinqs Intelligence links 3 tracked threat campaigns to CVE-2026-8451, 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-2026-8451?

Insufficient input validation in NetScaler ADC and NetScaler Gateway leading to memory overread if NetScaler ADC or NetScaler Gateway is configured as a SAML IDP

The record classifies CVE-2026-8451 under weakness class CWE-125. 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. 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: 7.5 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0 base score: 8.8
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N
EPSS (FIRST): 0.5% probability of exploitation in the next 30 days, higher than 39.2% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 7.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-06-30

Is CVE-2026-8451 being exploited?

Weaponised exploit code for CVE-2026-8451 is publicly available. 3 public proof-of-concept repositories are tracked for this identifier.

watchtowrlabs/watchTowr-vs-Netscaler-CVE-2026-8451 (github)
derekpreston81/CVE_ADC_IOC_2026 (github)
attarwahyup/Netscaler-CVE-2026-8451 (github)

Affected products and versions

NetScaler: ADC, Gateway

How to fix CVE-2026-8451

Vendor advisory: 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-2026-8451

3 tracked threats in the Threadlinqs corpus reference CVE-2026-8451, 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 — 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 — HIGH · 2026-07-02
CitrixBleed 2.0: CVE-2026-8451 NetScaler SAML IDP Memory Overread Under Active Exploitation — CRITICAL · 2026-06-30

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. 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

Full detection coverage & IOCs for threats exploiting CVE-2026-8451 are available via the Threadlinqs MCP server (Purple tier). View plans →

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