CVE detail
CVE-2026-35209
defu is software that allows uers to assign default properties recursively. Prior to version 6.1.5, applications that pass unsanitized user input (e.g. parsed JSON request bodies, database records, or config files from untrusted sources) as the first argument to `defu()` are vulnerable to prototype pollution. A crafted payload containing a `__proto__` key can override intended default values in the merged resul. The internal `_defu` function used `Object.assign({}, defaults)` to copy the defaults object. `Object.assign` invokes the `__proto__` setter, which replaces the resulting object's `[[Prototype]]` with attacker-controlled values. Properties inherited from the polluted prototype then bypass the existing `__proto__` key guard in the `for...in` loop and land in the final result. Version 6.1.5 replaces `Object.assign({}, defaults)` with object spread (`{ ...defaults }`), which uses `[[DefineOwnProperty]]` and does not invoke the `__proto__` setter.
Buzz score
Why this CVE is surfacing
This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.
Buzz score components · mention 16.1 · diversity 5.0 · KEV 0.0 · OTX 0.0 · PoC 0.0
Why it matters now
Mention timeline
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Evidence
Source links by recency
4 source links · newest first
No excerpt available.
Exploitgithub.comApr 6, 2026, 6:16 PMNo excerpt available.
Exploitgithub.comApr 6, 2026, 6:16 PM- https://github.com/unjs/defu/pull/156github.com
No excerpt available.
Exploitgithub.comApr 6, 2026, 6:16 PM No excerpt available.
Exploitgithub.comApr 6, 2026, 6:16 PM
Exploit code
Public exploit repository references
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0 repository references · best confidence N/A · max 0 stars
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