CVE-2021-48012 fast-toml - Prototype Pollution

fast-toml <= 0.5.4 contains a prototype pollution vulnerability caused by parsing TOML with __proto__, constructor, or prototype keys, letting attackers cause denial of service or authorization bypass, exploit requires crafted TOML input.

CVSS base score 8.2 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.41% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Prototype Pollution
Impact
Denial Of Service, Broken Access Control
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Published
12 October 2026
Updated
15 October 2026
Weakness
CWE-1321

Vendor fix

Update to the latest version beyond 0.5.4.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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