CVE-2021-48012

Published: Oct 12, 2026Modified: Oct 16, 2026Deferred

8.8

Vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XShow less

Source: disclosure@vulncheck.com (Secondary)

Description

fast-toml through 0.5.4 contains a prototype pollution vulnerability that allows attackers to modify Object.prototype by supplying TOML containing __proto__, constructor or prototype key segments. Attackers can pass [__proto__] or [constructor.prototype] table headers or __proto__.x dotted keys to parse() to pollute all objects, causing denial of service or authorization bypass.

Related CWEs

CWE-1321

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

References (4)

https://github.com/Gin-Quin/fast-toml

Source: disclosure@vulncheck.com

https://github.com/Gin-Quin/fast-toml/issues/8

Source: disclosure@vulncheck.com

https://github.com/Gin-Quin/fast-toml/pull/3

Source: disclosure@vulncheck.com

https://www.vulncheck.com/advisories/fast-toml-through-0.5.4-prototype-pollution-via-proto-keys-in-parsed-toml

Source: disclosure@vulncheck.com

Timeline

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