Medium 5.9Published Jun 9, 2026

CVE-2026-42567Svelte: ReDoS in `<svelte:element>` Tag Validation

Updated under an hour ago (Oct 26, 2026, 5:50 PM ET)

Does this affect you?

It affects sveltejs svelte and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for sveltejs svelte

Exploited in the last 30 days

Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in <svelte:element this={tag}></svelte:element>. This issue has been patched in version 5.55.7.

CVSS: 5.9 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE): CWE-1333
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jun 9, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

sveltejs svelte sveltejs:svelte (from the name)	from 5.51.5, < 5.55.7	CNA record
svelte svelte svelte:svelte	from 5.51.5 before 5.55.7	NVD

References

References

https://github.com/sveltejs/svelte/security/advisories/GHSA-9rmh-mm8f-r9h6	x-refsource-confirm, vendor-advisory
https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7	x-refsource-misc, product, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.