CVE-2026-123564

Sveltejs devalue before 5.9.3 Memory Exhaustion via uneval Sparse Arrays

Published Nov 8, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.
Title Sveltejs devalue before 5.9.3 Memory Exhaustion via uneval Sparse Arrays
First Time appeared Svelte
Svelte devalue
Weaknesses CWE-770
CPEs cpe:2.3:a:svelte:devalue:*:*:*:*:*:*:*:*
Vendors & Products Svelte
Svelte devalue
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 12, 2026, 1:02 PM
Reserved
Nov 6, 2026, 12:50 AM
Status
Awaiting Analysis
Published
Nov 8, 2026, 2:16 AM
Modified
Nov 12, 2026, 8:28 PM