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TI-2021-22760 Aliases CVE-2021-48012GHSA-qqfj-vf92-g76j

Prototype pollution in fast-toml via __proto__ keys in parsed TOML

Priority MEDIUM 44CWE-1321Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · High · Low
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

fast-toml through 0.5.4 contains a prototype pollution flaw, an improperly controlled modification of object prototype attributes (CWE-1321). Attackers can supply TOML with __proto__, constructor or prototype key segments to parse() to modify Object.prototype and thereby affect all objects. An unauthenticated remote attacker can cause denial of service or an authorization bypass.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00414 36th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Gin-Quinfast-tomlup to 0.5.4—No fix listedCNA
  • fast-toml VendorGin-Quin Affected up to 0.5.4 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for fast-toml.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-12 Threatist record created from CVE-2021-48012
  2. 2026-10-13 Alias added: GHSA-qqfj-vf92-g76j
  3. 2026-10-13 Priority changed: MEDIUM → LOW
  4. 2026-10-26 CISA SSVC decision points changed
  5. 2026-10-26 Priority changed: LOW → MEDIUM
  6. 2026-11-06 Affected versions changed · Red Hat
  7. 2026-11-06 CVSS score added · Red Hat

References

Patch 1

Other 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences