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 122 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. It currently carries a trending score of 52 in the Threadlinqs vulnerability feed.
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
4 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 2 (CVE-2025-5777) Exploited by Anubis Ransomware Affiliates Alongside Valid VPN Credentials and RMM Tool Abuse — CRITICAL · 2026-10-27
- 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 . This product uses the NVD API but is not endorsed or certified by the NVD.