Unrated

Memory Overflow DoS in NetScaler ADC/Gateway Oracle LB and DNS Features

IdentifiersCVE-2026-8655CWE-787

CVE-2026-8655 is a set of multiple memory overflow vulnerabilities affecting NetScaler ADC and NetScaler Gateway. The flaws are described by Citrix/NetScaler as causing memory corruption that leads to unpredictable or erroneous behavior and denial of service. Based on the available information, the vulnerable conditions are present when NetScaler ADC is configured as a load balancer of type Oracle, as a DNS Proxy, or as a DNS recursive resolver deployment. The specific vulnerable function or code path is not identified in the provided content.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can trigger memory corruption resulting in unstable appliance behavior, erroneous processing, and denial of service. The provided sources do not describe confirmed impacts beyond service disruption or indicate arbitrary code execution; the documented impact is disruption of availability and unpredictable runtime behavior in affected NetScaler deployments.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by identifying whether the appliance is configured in any of the affected modes and disabling or restricting those features where operationally feasible: Oracle-type load balancing, DNS Proxy, and DNS recursive resolver deployments. More generally, review NetScaler configurations to determine whether the stated preconditions for this CVE are present and minimize remote access paths to affected services until upgrades are completed. No specific vendor workaround beyond patching is provided in the supplied content.

Remediation

Patch, then assume compromise.

Upgrade affected systems to vendor-fixed releases. The provided advisory states fixes are available in NetScaler ADC and NetScaler Gateway 14.1-72.61 and later, NetScaler ADC and NetScaler Gateway 13.1-63.18 and later in the 13.1 branch, NetScaler ADC 14.1-FIPS 14.1-72.61 FIPS and later, and NetScaler ADC 13.1-FIPS / 13.1-NDcPP 13.1-37.272 and later. Review Citrix security bulletin ctx696604 and apply the relevant fixed build for the deployed product line.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Citrix SystemsNetscaler Adcapplication

Citrix SystemsNetscaler Gatewayapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

9 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

9 SOURCESView more in app

cyber security newsNews

Jul 1, 2026

Multiple Citrix NetScaler ADC and Gateway Vulnerabilities Enables DoS and Memory Overflow Attacks

A high-severity vulnerability in Citrix NetScaler ADC and NetScaler Gateway related to improper memory handling and insufficient input validation that can be exploited to cause denial-of-service or memory overflow conditions.

security weekNews

Jul 1, 2026

Citrix Patches NetScaler Vulnerabilities, Including New ‘HTTP/2 Bomb’ Attack - SecurityWeek

A high-severity NetScaler vulnerability fixed by Citrix; the article groups it among out-of-bounds read, memory overflow, and arbitrary file read bugs but does not map the exact bug type to this CVE.

the hacker newsNews

Jul 1, 2026

Citrix Patches Six NetScaler Flaws Allowing File Read and Denial-of-Service

Multiple memory overflow vulnerabilities in NetScaler ADC that can lead to erroneous behavior or denial of service in certain load balancing and DNS-related deployments.

malware newsNews

Jun 30, 2026

Citrix security advisory (AV26-645) - Malware News - Malware Analysis, News and Indicators

A critical vulnerability addressed by Citrix in NetScaler ADC, NetScaler Gateway, and related FIPS/NDcPP editions.

+2 more in the timeline

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-8655

NVD

nvd.nist.gov/vuln/detail/CVE-2026-8655

MITRE CWE · CWE-787

cwe.mitre.org