CVE-2018-8326: Microsoft Web Customizations: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Recommended actionScheduled

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

Patch available

What, why and how

A cross-site-scripting (XSS) vulnerability exists when an open source customization for Microsoft Active Directory Federation Services (AD FS) does not properly sanitize a specially crafted web request to an affected AD FS server, aka "Open Source Customization for Active Directory Federation Services XSS Vulnerability." This affects Web Customizations.

What

Why

Attacker-controlled content can reach a browser as executable script without sufficient output encoding or sanitisation.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

Attacker-controlled content can reach a browser as executable script without sufficient output encoding or sanitisation.

How

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 → Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Network
Privileges required: Low: a basic authenticated account is required
User interaction: Required interaction required
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Changed: exploitation can affect a different security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-79 ↗
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'). The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Common Vulnerability Scoring System 3.0: 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.PRLowPrivileges required: The attacker needs basic user-level privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SChangedScope: The attack can affect a component governed by a different security authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: 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.

NetworkCWE-79

Official authority intelligence

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

ENISA EUVD · EUVD-2018-19977Official EUVD mapping

0 linked advisory records.

Official EUVD record ↗

Canadian Centre for Cyber Security · English · AV18-112Microsoft security updates

This advisory covers multiple support package deployments addressing multiple vulnerabilities in various Microsoft products. Products Affected: Adobe Flash Player ASP.NET ChakraCore Internet Explorer PowerShell Editor Services PowerShell Extension for Visual Studio Code Microsoft Edge Microsoft Lync Microsoft Office Microsoft Office Services and Web Apps Microsoft Research JavaScript Cryptography Library Microsoft Visual Studio Microsoft Windows Microsoft Wireless Display Adapter V2 Software Microsoft .NET Framework Skype for Business Web Customizations for Active Directory Federation Services CVE References: CVE-2018-8260, CVE-2018-8281, CVE-2018-8282, CVE-2018-8282, CVE-2018-8299, CVE-2018-8300, CVE-2018-8310, CVE-2018-8323, CVE-2018-8326, CVE-2018-8327

Official advisory ↗

CERT-FR · French · CERTFR-2018-AVI-338Multiples vulnérabilités dans les produits Microsoft

.cve.org/CVERecord?id=CVE-2018-8288 Référence CVE CVE-2018-8290 https://www.cve.org/CVERecord?id=CVE-2018-8290 Référence CVE CVE-2018-8291 https://www.cve.org/CVERecord?id=CVE-2018-8291 Référence CVE CVE-2018-8294 https://www.cve.org/CVERecord?id=CVE-2018-8294 Référence CVE CVE-2018-8298 https://www.cve.org/CVERecord?id=CVE-2018-8298 Référence CVE CVE-2018-8306 https://www.cve.org/CVERecord?id=CVE-2018-8306 Référence CVE CVE-2018-8311 https://www.cve.org/CVERecord?id=CVE-2018-8311 Référence CVE CVE-2018-8312 https://www.cve.org/CVERecord?id=CVE-2018-8312 Référence CVE CVE-2018-8319 https://www.cve.org/CVERecord?id=CVE-2018-8319 Référence CVE CVE-2018-8326 https://www.cve.org/CVERecord?id=CVE-2018-8326 Référence CVE CVE-2018-8327 https://www.cve.org/CVERecord?id=CVE-2018-8327 Gestion détaillée du document le 11 juillet 2018 Version initiale Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À propos Contact cyber.gouv.fr service-public.fr legifrance.gouv.fr info.gouv.fr france.fr info.gouv.fr/risques Premier Ministre / Secrétariat Général de la Défense et de la Sécurité Nationale / Agence nationale de la sécurité des systèmes d'information

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2018-007133Web Customizations におけるクロスサイトスクリプティングの脆弱性

Web Customizations には、影響を受ける AD FS サーバーに対する巧妙に細工された Web リクエストを適切にサニタイズしない場合、クロスサイトスクリプティングの脆弱性が存在します。ベンダは、本脆弱性を「Active Directory フェデレーションサービスのオープンソースカスタマイズの XSS の脆弱性」として公開しています。

Official advisory ↗

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.: Patch available
Affected: Web Customizations: Active Directory Federation Services
Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
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.

Evidence and provenance

Published 11 Jul 2018 · Last source change 5 Aug 2024, 06:54 UTC · CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVE recordCVE.org · 5.1

CVSS sourceNIST NVD

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-09-01

European sourceENISA EUVD · EUVD-2018-19977

Product sourceCNA

Remediation sourceCVE/CNA references

CWE sourceNIST NVD

NVD statusNVD modified after enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗

1 Sep 2026, 02:42 UTC
ENISA EUVD mappingEUVD-2018-19977 was added to the official ENISA EUVD mapping for this CVE.
Before
not recorded
After
{"euvdId":"EUVD-2018-19977"}
ENISA EUVD ↗
5 Aug 2024, 06:54 UTC
Vendor guidanceAuthoritative vendor guidance changed: added patch: portal.msrc.microsoft.com/CVE-2018-8326; added remediation: portal.msrc.microsoft.com/CVE-2018-8326.
Before
no authoritative guidance recorded
After
patch: portal.msrc.microsoft.com/CVE-2018-8326 · remediation: portal.msrc.microsoft.com/CVE-2018-8326
portal.msrc.microsoft.com ↗
5 Aug 2024, 06:54 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
Active Directory Federation Services · Fixed: No fixed version is explicitly recorded in the structured CVE data.
After
Active Directory Federation Services · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
CNA ↗
5 Aug 2024, 06:54 UTC
Remediation statusRemediation status changed from Awaiting fix to Patch available.
Before
Awaiting fix
After
Patch available
portal.msrc.microsoft.com ↗
5 Aug 2024, 06:54 UTC
SeveritySeverity changed from Unknown to Medium.
Before
Unknown
After
Medium
NIST NVD ↗
5 Aug 2024, 06:54 UTC
CVSS scoreCVSS score changed from not recorded to 5.4 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N).
Before
not recorded
After
5.4 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N)
NIST NVD ↗
5 Aug 2024, 06:54 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2018-07-11CVE published

2024-08-05Fixed release or patch reference recorded

ENISA EUVD · EUVD-2018-19977↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

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.

Microsoft Web Customizations: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Published severity in operational context

Evidence used

Compensating controls

Verification

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

ENISA European Vulnerability Database

EUVD-2018-19977

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication