TI-2026-30879 Aliases CVE-2026-42599 GHSA-pr6f-5x2q-rwfp

Cross-site scripting via spread attributes in Svelte SSR

LOW 23CWE-79Published 2026-06-09 · Updated 2026-06-09

Key facts

Attack vector: Network
Privileges required: High
User interaction: None
Attack complexity: High
Attack requirements: Present
Impact type: Cross-site scripting
Confidentiality · integrity · availability: None · None · None
Fix status: Partial Red Hat: 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-79.

Summary

Svelte is a performance oriented web framework. Prior to version 5.55.7, when using spread syntax to render attributes from untrusted data, event handler properties are included in the rendered HTML output. If an application spreads user-controlled or external data as element attributes, an attacker can inject malicious event handlers that execute in victims' browsers. Note that this vulnerability only triggers if the user's browser has JavaScript enabled but Svelte's hydration mechanism does not reach the vulnerable element before the event fires. This issue has been patched in version 5.55.7.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00205 10th percentileScored 2026-11-07

Fix Partial svelte (sveltejs): 5.55.7svelte (npm): 5.55.7Red Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
sveltejs	svelte	before 5.55.7	5.55.7	Patch available	CNA
—	svelte (npm)	before 5.55.7	5.55.7	Patch available	GHSA-pr6f-5x2q-rwfp

svelte Vendorsveltejs Affected before 5.55.7 Fixed in 5.55.7 Patch available CNA
svelte (npm) Vendor— Affected before 5.55.7 Fixed in 5.55.7 Patch available GHSA-pr6f-5x2q-rwfp

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:svelte:svelte::::::node.js::*	before 5.55.7	Vulnerable	sveltejs

cpe:2.3:a:svelte:svelte:*:*:*:*:*:node.js:*:* Versions before 5.55.7 Vulnerable ·sveltejs

Remediation

Fix · CNA svelte (sveltejs) Fixed in 5.55.7
Fix · GHSA-pr6f-5x2q-rwfp svelte (npm) Fixed in 5.55.7 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Build of Podman Desktop	Affected	No fix yet: Fix deferred
Red Hat Build of Podman Desktop - Tech Preview	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-42599
2026-10-03 Alias added: GHSA-pr6f-5x2q-rwfp

References

Advisory 3

Other 2

TI-2024-30159 Potential mXSS vulnerability due to improper HTML escaping in svelte CVSS 3.1MEDIUM 6.1
TI-2025-13940 Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR) CVSS 4.0MEDIUM 5.3
TI-2021-10070 The unofficial Svelte extension before 104.8.0 for Visual Studio Code allows attackers to… CVSS 3.1HIGH 7.8
TI-2022-09436 Cross-site scripting (XSS) in svelte CVSS 3.1MEDIUM 6.1
TI-2026-30847 Svelte: ReDoS in `<svelte:element>` Tag Validation CVSS 4.0MEDIUM 5.9
TI-2026-30853 Svelte: XSS via DOM Clobbering of Internal Framework State CVSS 4.0MEDIUM 5.3

See all 12 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences