How severe is CVE-2026-42567?

CVE-2026-42567 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-42567 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42567?

CVE-2026-42567 affects Svelte. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42567?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42567 have an EU (EUVD) identifier?

Yes. CVE-2026-42567 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35702.

When was CVE-2026-42567 published?

CVE-2026-42567 was published on 2026-06-09 and last updated on 2026-06-17.

CVE-2026-42567

CVE-2026-42567 is a high-severity vulnerability in Svelte with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1333.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 5.9
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35702
Weakness: CWE-1333
Affected product: Svelte
Published: 2026-06-09
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-42567?: 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.
How severe is CVE-2026-42567?: CVE-2026-42567 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-42567 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42567?: CVE-2026-42567 affects Svelte. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42567?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42567 have an EU (EUVD) identifier?: Yes. CVE-2026-42567 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35702.
When was CVE-2026-42567 published?: CVE-2026-42567 was published on 2026-06-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:svelte:svelte:*:*:*:*:*:node.js:*:*

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