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CVE-2026-27902

Svelte Vulnerable to XSS via HTML Comment Injection in SSR Error Boundary Hydration Markers

Published: Feb 26, 2026Updated: Mar 5, 2026 Sources: CVE List NVD GHSACWE-79
5.4MEDIUM
NVD MITRE
EPSS Score
0.2%
Top 86.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:UC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-79

Affected Products

sveltesveltejs
Library
OSS Libraries / web-framework
sveltesvelte
Library
OSS Libraries / web-framework
sveltenpmOSS Libraries
sveltejsoss-projectOSS Libraries
svelteoss-projectOSS Librariesaka kit, sveltekit
npmpackage-ecosystemOSS Libraries

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://github.com/sveltejs/svelte/security/advisories/GHSA-qgvg-pr8v-6rr3
github.com
https://github.com/sveltejs/svelte/commit/0298e979371bb583855c9810db79a70a551d22b9
github.com
https://github.com/sveltejs/svelte/releases/tag/svelte%405.53.5
github.com
and 3 more references View all →

Timeline

Published
Feb 26, 2026
Last Updated
Mar 5, 2026

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