Widely deployed Citrix NetScaler ADC/Gateway; DoS could disrupt many orgs.
CVE-2026-8655
Memory overflow in Citrix NetScaler ADC/Gateway causes DoS in LB/DNS modes.
Is CVE-2026-8655 being exploited?
Not confirmed. CVE-2026-8655 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.63% probability of exploitation in the next 30 days.
How severe is CVE-2026-8655?
CVE-2026-8655 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-8655?
Yes. A fix has been recorded for CVE-2026-8655. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-8655 affect?
CVE-2026-8655 affects Citrix NetScaler ADC, Citrix NetScaler Gateway. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-8655?
Plan patching when vendor release; monitor LB/DNS traffic.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
DoS via memory overflow; crashes or unpredictable behavior when NetScaler acts as LB or DNS proxy/resolver.
Patch when possible
- affected>= 14.1 and < 72.61
- affected>= 13.1 and < 63.18
- affected>= 14.1 FIPS and < 72.61
- affected>= 13.1 FIPS and NDcPP and < 37.272
- affected>= 14.1 and < 72.61
- affected>= 13.1 and < 63.18
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.