CVE-2026-123565sveltejs devalue Uncontrolled Resource Consumption
NVD
Vulnerability Summary
Sveltejs devalue before 5.9.3 contains a resource exhaustion vulnerability where repeated primitive strings cause quadratic expansion in the uneval function. Attackers can supply a small crafted payload that is parsed and then passed to uneval, producing a very large serialized string that exhausts memory or CPU.
CVSS v4.0 Base Metrics — Score 8.7 (HIGH)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NAttack VectorNetwork
Attack ComplexityLow
Attack RequirementsNone
Privileges RequiredNone
User InteractionNone
Confidentiality (Vulnerable System)None
Integrity (Vulnerable System)None
Availability (Vulnerable System)High
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)None
Show CVSS v3.x metrics (score 7.5)
CVSS v3.1 Base Metrics — Score 7.5 (HIGH)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HAttack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
Affected & Patched Versions
- sveltejs devalue < 5.9.3
- sveltejs devalue 5.9.3
What to do
Plan remediation soon. No exploitation is confirmed yet, but the severity is high.
- Check whether you run sveltejs devalue and which version.
- Update to a patched version listed above, then confirm the new version.
Timeline
- Nov 8, 2026Published
- Nov 10, 2026Record last modified
Score, severity and exploitation changes are tracked from the day Watchtower started logging them.
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External References
Data last checked: Nov 14, 2026 02:13 UTC