8.7
High
CVE-2026-123566 Devalue before 5.9.3 CPU Amplification Denial of Service via uneval
Description
Sveltejs devalue before 5.9.3 contains a denial of service vulnerability that allows attackers to cause CPU amplification by supplying sparse arrays to uneval. Attackers who influence sparse values passed to uneval can force synchronous work proportional to the declared array length, blocking the event loop.
CVSS 4.0 detail
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:NExploitable remotely over the network, without an account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- Interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
- Confidentiality of other systems
- None
- Integrity of other systems
- None
- Availability of other systems
- None
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| devalue 5.9 | earliest → < 5.9.3 | 5.9.3 |
Other CVEs of devalue
The 16 CVEs of devalue →
CVE-2026-123569
Devalue before 5.6.3 Denial of Service via Sparse Array Serialization
8.7
High
CVE-2026-123568
Sveltejs devalue before 5.6.3 Prototype Pollution via uneval Output
2.1
Low
CVE-2026-123567
Sveltejs devalue before 5.6.4 Prototype Injection via parse and unflatten
6.3
Medium
CVE-2026-123565
Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval
8.7
High