ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `</textarea/>` solidus close

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63670
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-17 20:16:45 UTC
Updated2026-08-18 18:19:12 UTC
DescriptionApostropheCMS is an open-source Node.js content management system. Prior to 2.17.6, sanitizeHtml() can pass disallowed executable markup through packages/sanitize-html/index.js when textarea or xmp is included in allowedTags because a literal solidus after the raw-text end-tag name is treated as text by htmlparser2 and the ontext handler emits that content without escaping, while a browser parses the following img onerror markup as active HTML. This issue is fixed in version 2.17.6.

Risk And Classification

Primary CVSS: v3.1 6.1 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS: 0.002360000 probability, percentile 0.147510000 (date 2026-08-18)

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

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
3.1CNADECLARED6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apostrophecms Apostrophe affected < 2.17.6 Not specified

References

ReferenceSourceLinkTags
github.com/apostrophecms/apostrophe/security/advisories/GHSA-jxwj-j7wr-gfrw 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/apostrophecms/apostrophe/commit/eae1fb2b72ec5d1c27d0977509c64... [email protected] github.com
github.com/apostrophecms/apostrophe/pull/5501 [email protected] github.com
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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