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 . This issue has been patched in version 5.55.7.
CVE-2026-42567
HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 66% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 34.0%
- KEV
- Not listed
Published
June 9, 2026
Last Modified
June 11, 2026
Advisory Details (2)
Auto-updated Jun 11, 2026Patch available. Sources: github_release, github.
github Patch Available
ReDoS in `<svelte:element>` Tag Validation · Advisory · sveltejs/svelte · GitHub
https://github.com/sveltejs/svelte/security/advisories/GHSA-9rmh-mm8f-r9h6github_release Patch Available
[email protected]
Patch available: sveltejs/svelte [email protected]
https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7Vendor Advisories for CVE-2026-42567(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Frequently asked(5)
What is CVE-2026-42567?
CVE-2026-42567 is a high vulnerability published on June 9, 2026. 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.
When was CVE-2026-42567 disclosed?
CVE-2026-42567 was first published in the National Vulnerability Database on June 9, 2026, with the most recent update on June 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42567 actively exploited?
CVE-2026-42567 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 34.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42567?
CVE-2026-42567 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-42567?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42567, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-42567
Is Your Infrastructure Affected by CVE-2026-42567?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.