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CVE-2026-84371

ApostropheCMS: Stored XSS via SVG SMIL URI-list scheme-policy bypass

CVSS score

5.4

EPSS probability

%0.3

Risk score

0.0

Published

1 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Official patch verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-84371 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. From version 1.9.0 until version 2.17.7, packages/sanitize-html/index.js validates an animation value attribute as one flat URL and does not recognize that attributeName selecting href or xlink:href gives the sibling values, from, to, or by attribute SVG SMIL URL semantics. In configurations that allow the animate, animateColor, animateMotion, animateTransform, or set elements, a values list can begin with a safe fragment and contain a later executable destination that survives allowedSchemesAppliedToAttributes checking. When the sanitized SVG is rendered, the browser can copy that later destination into the live link, and a victim who activates the link can execute script in the application's origin. This issue is fixed in version 2.17.7.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-84371 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1apostrophecmsapostrophe View
2npmsanitize-html View
3npmsanitize-html View
Total affected vendors: 2|Products: 3

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
5.4CVSS 3.x—Vector not publishedGitHub Advisory
5.4CVSS V3_1MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NCVE CNA
5.4CVSS V31MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NNVD
0.0CVSS 4.0—Vector not publishedGitHub Advisory

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

osvsanitize-html2.17.7

OSV düzeltilmiş sürüm: 2.17.7

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-84371 is associated with the following CWEs:

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-84371 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsLow
UserGerekiyor

Official Sources and Advisories

https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-g8qq-57p8-ggw5vendor-advisoryhttps://github.com/apostrophecms/apostrophe/pull/5552vendor-advisoryhttps://github.com/apostrophecms/apostrophe/commit/1135516a1a4a8f9638641c460488a43d8af20081vendor-advisoryhttps://github.com/apostrophecms/apostrophe/commit/38ff1106c8176b16c2da9872acd9b449adcbb949vendor-advisoryhttps://github.com/apostrophecms/apostrophe/blob/main/packages/sanitize-html/CHANGELOG.mdvendor-advisoryhttps://github.com/advisories/GHSA-g8qq-57p8-ggw5vendor-advisoryhttps://github.com/apostrophecms/apostrophevendor-advisory

CVSS Vector Radar Chart

5.4 / 10
Attack VectorNetworkComplexityLowPrivilegesLowUser Interact.RequiredConfidentialityLowIntegrityLowAvailabilityNone

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow privileges
User Interaction—
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)Low
Availability (Erişilebilirlik)None

Yama doğrulandı

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

A
apostrophecms logo
apostrophecms
N
npm logo
npm

Weakness Type (CWE & CAPEC)

CWE-79

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