CVE-2020-28462Public exploitNetwork attack vector

Prototype pollution via unchecked __proto__ table assignment

Published Jul 25, 2022 · Updated Sep 16, 2024

Prototype pollution in Lepzulnag ion-parser 0.5.2 and earlier allows remote attackers to modify Object.prototype via crafted TOML input. The parse function accepts a [proto] table and assigns its attacker-controlled properties through the inherited proto accessor without rejecting that special key. The host application must pass attacker-controlled configuration text to parse; the resulting inherited properties affect other objects, while further security impact requires a suitable application gadget.

CVSS severity9.8
Critical
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prototype pollution in Lepzulnag ion-parser 0.5.2 and earlier allows remote attackers to modify Object.prototype via crafted TOML input. The parse function accepts a [proto] table and assigns its attacker-controlled properties through the inherited proto accessor without rejecting that special key. The host application must pass attacker-controlled configuration text to parse; the resulting inherited properties affect other objects, while further security impact requires a suitable application gadget.

The record

CVE
CVE-2020-28462
Published
Jul 25, 2022
Updated
Sep 16, 2024
Vendor
Lepzulnag
Product
ion-parser
Classifications
CWE-1321
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 25, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Lepzulnag · ion-parserversion=0 <unspecified

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.9SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P
7.3SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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