Bug 2487114 (CVE-2026-42567)

Summary: CVE-2026-42567 svelte: Svelte: Regular Expression Denial of Service (ReDoS)
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: cdrage, rushinde
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Svelte, a web framework. An internal regular expression (regex) in the Svelte runtime, specifically when processing `<svelte:element this={tag}></svelte:element>`, can be exploited by a remote attacker. By providing specially crafted input, an attacker can cause the regex to take an exponential amount of time to process, leading to a Regular Expression Denial of Service (ReDoS) condition. This can make the affected application unresponsive or unavailable to legitimate users.
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Description OSIDB Bzimport 2026-06-09 18:03:05 UTC
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.