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Fencer Intel
high 8.8

CVE-2026-114142 json

toml-node: Prototype pollution: parsing a TOML document can write to Object.prototype

published 19d ago modified 12d ago also GHSA-h895-cgqg-jf52 , EUVD-2026-107553

cvss
8.8
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

toml-node is a TOML parser for Node.js and the browser. Prior to 5.0.1, toml.parse() can write attacker-controlled properties to Object.prototype because quoteDottedString() in lib/compiler.js produces the same bookkeeping string for distinct quoted key paths, allowing addTableArray() to clear another key's guard. The assign() path then descends through an unowned Date value without applying the owned-container check and can reach the prototype chain. Objects created elsewhere in the process can inherit the injected property. This issue is fixed in version 5.0.1.

Patch / fix

  • npm toml 5.0.1

Is CVE-2026-114142 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
12d ago

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 8.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/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

Affected packages

ecosystem package affected fixed in
npm toml
<5.0.1
5.0.1

Affected products

  • BinaryMuse toml-node

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.