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Full vulnerability report · 2026
CVE-2026-10817High confidence

Insufficient input validation leading to memory overread

NetScaler · ADC

6.9MediumCVSS 4.0
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Mitigation available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.56% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs NetScaler ADC and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-40317

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Mitigation available
01

What, why and how

Insufficient input validation leading to memory overread in NetScaler ADC and NetScaler Gateway if the TCP TimeStamp is enabled in TCP Profile and is associated with the virtual server (of type LB, CS, VPN) or the service configured on NetScaler

What

Insufficient input validation leading to memory overread in NetScaler ADC and NetScaler Gateway if the TCP TimeStamp is enabled in TCP Profile and is associated with the virtual server (of type LB, CS, VPN) or the service configured on NetScaler

Why

The product reads data past the end, or before the beginning, of the intended buffer.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Insufficient input validation leading to memory overread in NetScaler ADC and NetScaler Gateway if the TCP TimeStamp is enabled in TCP Profile and is associated with the virtual server (of type LB, CS, VPN) or the service configured on NetScaler

Why

The product reads data past the end, or before the beginning, of the intended buffer.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Out-of-bounds Read → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-125 ↗

CWE-125: Out-of-bounds Read. The product reads data past the end, or before the beginning, of the intended buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCLowVulnerable-system confidentiality: A successful attack can cause a limited loss.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-125
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2026-2147Citrix Systems NetScaler ADC und Gateway: Mehrere Schwachstellen

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Citrix Systems NetScaler ADC und Gateway ausnutzen, um Informationen offenzulegen, einen Denial-of-Service-Zustand zu verursachen oder andere, nicht näher spezifizierte Auswirkungen auszulösen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AL26-016AL26-016 - Vulnerability impacting Citrix NetScaler CVE-2026-8451

An Alert is used to raise awareness of a recently identified cyber threat that may impact cyber information assets, and to provide additional detection and mitigation advice to recipients. The Canadian Centre for Cyber Security ("Cyber Centre") is also available to provide additional assistance regarding the content of this Alert to recipients as requested.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-645Citrix security advisory (AV26-645) – Update 3

On June 30, 2026, Citrix published a security advisory to address critical vulnerabilities in the following products: Open-source reporting indicates that CVE-2026-8451 is being exploited.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260701Security Bulletin 1 July 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 1 July 2026, published on 1 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0822Multiples vulnérabilités dans les produits Citrix

De multiples vulnérabilités ont été découvertes dans les produits Citrix. Certaines d'entre elles permettent à un attaquant de provoquer un déni de service à distance, une atteinte à la confidentialité des données et un problème de sécurité non spécifié par l'éditeur.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-022226シトリックス・システムズのnetscaler application delivery controller等の複数製品における境界外読み取りに関する脆弱性

TCPプロファイルでTCPタイムスタンプが有効になっており、NetScalerの仮想サーバー(LB、CS、VPNのいずれかのタイプ)またはNetScalerに設定されたサービスに関連付けられている場合に、不十分な入力検証によってメモリのオーバーリードが発生する問題が存在します。

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0216Kwetsbaarheden verholpen in Citrix Netscaler ADC en Netscaler Gateway

De kwetsbaarheden met de kenmerken CVE-2026-8451 en CVE-2026-10817 ontstaan door onvoldoende invoervalidatie, waarbij de software invoergroottes en -grenzen niet correct controleert. Dit kan leiden tot geheugenoverlezingen, wat kan resulteren in ongeautoriseerde openbaarmaking van gevoelige informatie, wanneer de producten zijn geconfigureerd als SAML IDP, of als TCP TimeStamp is ingeschakeld bij een TCP-profiel dat is gekoppeld aan een virtuele server van het type: Load Balancing (LB), Content Switching (CS) of VPN. De kwetsbaarheden met de kenmerken CVE-2026-8452 en CVE-2026-8655 bevinden zich in de manier waarop geheugen wordt beheerd in NetScaler ADC en NetScaler Gateway. Dit kan leiden tot een denial-of-service (DoS) of een ongewenste control flow wanneer de producten zijn geconfigureerd als Gateway, DNS-proxy, recursieve DNS-resolver of AAA-virtuele server. De kwetsbaarheid met het kenmerk CVE-2026-13474 ontstaat door het onjuist vrijgeven van geheugen. Kwaadwillenden kunnen deze kwetsbaarheid misbruiken door via speciaal geprepareerde HTTP/2-verzoeken een denial-of-service (DoS) te veroorzaken. De kwetsbaarheid met het kenmerk CVE-2026-10816 betreft een probleem met de toegangscontrole binnen de Management Interface. Niet-geauthenticeerde kwaadwillenden op afstand kunnen de kwetsbaarheid misbruiken om willekeurige bestanden uit te lezen. Dit kan resulteren in ongeautoriseerde openbaarmaking van gevoelige informatie. Onderzoekers hebben Proof-of-Concept (PoC) code gedeeld waarmee de kwetsbaarheid met kenmerk CVE-2026-8451 kan worden aangetoond. **UPDATE:** Inmiddels hebben dezelfde onderzoekers ook Proof-of-Concept (PoC) code gepubliceerd waarmee uitvoer van willekeurige code mogelijk wordt. Het kwetsbare systeem moet hiervoor wel zijn geconfigureerd om middels SAML ingezet te zijn als Identity Provider. Dit is geen gebruikelijke configuratie, omdat best practices adviseren het Identity Management en Access Management gescheiden te houden.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Mitigation available
Affected
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
The Cyber Centre encourages users and administrators to review the provided web links and apply the necessary updates.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 30 Jun 2026 · Last source change 30 Jun 2026, 13:28 UTC · CWE-125 · Out-of-bounds Read

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-40317
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Canadian Centre for Cyber Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-10817 · cve.blacktree.nl