CVE-2026-123562— Devalue 5.8.0 before 5.9.3 Denial of Service via stringifyAsync Unhandled Rejection

Quick assessment

Affected

sveltejs devalue

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

（sveltejs/devalue）版本 5.8.0 至 5.9.2 中存在一个未处理的 Promise 拒绝漏洞，该问题出现在函数中：当序列化多个 Promise 时，若后一个 Promise 在前一个 Promise 完成之前被拒绝（reject），则会导致内部拒绝未被处理，即使调用方已捕获返回的 Promise。能够影响被序列化的异步值的时序或失败状态的攻击者，可利用此漏洞终止 Node.js 进程。

CVSS 7.5 · High Updated Nov 08, 2026

Possible ATT&CK Techniques 1 AI

T1569 · System Services

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Vulnerability Information

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Vulnerability Title

Devalue 5.8.0 before 5.9.3 Denial of Service via stringifyAsync Unhandled Rejection

Source: CVE Program / CVE List V5

Vulnerability Description

devalue (sveltejs/devalue) 5.8.0 before 5.9.3 contains an unhandled promise rejection in stringifyAsync: when serializing multiple promises, a later promise rejecting before an earlier one settles leaves an internal rejection unhandled, even if the caller catches the returned promise. An attacker able to influence the timing or failure of serialized asynchronous values can terminate the Node.js process.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

未捕获的异常

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
sveltejs	devalue	5.8.0 ~ 5.9.3	-

II. Public POCs for CVE-2026-123562

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-123562

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Other References for CVE-2026-123562 (2)

https://github.com/sveltejs/devalue/security/advisories/GHSA-x5rw-q4pp-hg5g vendor-advisory
https://www.vulncheck.com/advisories/devalue-5.8.0-before-5.9.3-denial-of-service-via-stringifyasync-unhandled-rejection third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-123562

Same Patch Batch · sveltejs · 2026-11-08 · 9 CVEs total

CVE-2026-123564	7.5 HIGH	Sveltejs devalue before 5.9.3 Memory Exhaustion via uneval Sparse Arrays
CVE-2026-123566	7.5 HIGH	Devalue before 5.9.3 CPU Amplification Denial of Service via uneval
CVE-2026-123569	7.5 HIGH	Devalue before 5.6.3 Denial of Service via Sparse Array Serialization
CVE-2026-123563	7.5 HIGH	Devalue before 5.9.3 Typed-Array Allocation Validation Bypass via parse
CVE-2026-123565	7.5 HIGH	Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval
CVE-2026-123568	4.4 MEDIUM	Sveltejs devalue before 5.6.3 Prototype Pollution via uneval Output
CVE-2026-123567	3.7 LOW	Sveltejs devalue before 5.6.4 Prototype Injection via parse and unflatten
CVE-2026-123561	3.7 LOW	Sveltejs devalue before 5.9.3 __proto__ Rejection Bypass via Property-Key Coercion

IV. Related Vulnerabilities

Same product: devalue

Same vendor: sveltejs

Same weakness: CWE-248