CVE-2021-48012CWE-1321

CVE-2021-48012

High · published October 13, 2026

CVSS v3.1
8.2
EPSS
0%
Percentile
34.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.2 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
CVSS v4.0
8.8 · 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
EPSS
0.00414 · 34.7th percentile
Weakness
CWE-1321 · Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Published
2026-10-13T01:17Z
References (4)
https://github.com/Gin-Quin/fast-toml · [email protected]https://github.com/Gin-Quin/fast-toml/issues/8 · [email protected]https://github.com/Gin-Quin/fast-toml/pull/3 · [email protected]https://www.vulncheck.com/advisories/fast-toml-through-0.5.4-prototype-pollution-via-proto-keys-in-parsed-toml · [email protected]
EPSS history
Timeline
  • 14 OCT 03:15Z
    EPSS moved — → 0%
    epss
  • 12 OCT 20:55Z
    fast-toml through 0.5.4 Prototype Pollution via __proto__ Keys in Parsed TOML
    cvelistv5
  • 12 OCT 20:55Z
    fast-toml through 0.5.4 Prototype Pollution via __proto__ Keys in Parsed TOML
    cvelistv5