CVE-2026-123567: medium-severity vulnerability in sveltejs devalue
Sveltejs devalue before 5.6.4 Prototype Injection via parse and unflatten
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.3epss 0.2%
Sveltejs devalue before 5.6.4 contains a prototype injection vulnerability that allows attackers to inject __proto__ own properties into objects returned by devalue.parse and devalue.unflatten. Attackers can supply crafted serialized input that, when downstream code merges results via Object.assign, alters the target object's prototype.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Affected products
sveltejs · devalueRelated CVEs — sveltejs devalue
In the same product, most dangerous first.
CVE-2026-92708HIGHdevalue: Cross-request process memory disclosure in devalue when `stringify` / `uneval` serialize Node BuffersEPSS 0.7%CVE-2026-22775HIGHdevalue vulnerable to denial of service due to memory/CPU exhaustion in devalue.parseEPSS 0.6%CVE-2026-22774HIGHdevalue vulnerable to denial of service due to memory exhaustion in devalue.parseEPSS 0.6%CVE-2026-81176MEDIUMSvelte devalue: DoS via malformed inputEPSS 0.5%CVE-2026-30226MEDIUMdevalue has prototype pollution in devalue.parse and devalue.unflattenEPSS 0.5%CVE-2026-42570HIGHSvelte devalue: DoS via sparse array deserializationEPSS 0.4%