Cyber Resilience

CVE-2026-42567

Medium

Published: 09 June 2026

Published
09 June 2026
Modified
11 June 2026
KEV Added
—
Patch
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CVSS Score v4 5.9 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0042 33.6th percentile
Risk Priority 12 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-42567 is a medium-severity Inefficient Regular Expression Complexity (CWE-1333) vulnerability in Svelte Svelte. Its CVSS base score is 5.9 (Medium).

Operationally, ranked at the 33.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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.

CWE(s)
CWE-1333

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

svelte
svelte
5.51.5 — 5.55.7

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References