RubyGems up to 28.2.x Metadata Validation prototype pollution

CVSS Meta Temp Score
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CTI Interest Score
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4.5$0-$5k0.00+

Summaryinfo

A vulnerability, which was classified as problematic, was found in RubyGems up to 28.2.x. This affects an unknown function of the component Metadata Validation. The manipulation results in prototype pollution. This vulnerability is cataloged as CVE-2026-118389. The attack may be launched remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in RubyGems up to 28.2.x. Affected is some unknown functionality of the component Metadata Validation. The manipulation with an unknown input leads to a prototype pollution vulnerability. CWE is classifying the issue as CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

The RubyGems package registry accepted gems whose platform, dependency names or dependency version requirements contain newline characters. Because the compact index served to clients is line-based, a user who can publish a gem to an owner's registry could forge index entries, such as packages that do not exist or additional versions of an existing gem with dependencies of their choice. Clients that resolve gems from that registry could then be led to install attacker-chosen dependencies. Gems with such metadata are now rejected.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-118389 since 11/15/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Additional levels of successful authentication are needed for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 28.3.0 eliminates this vulnerability.

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Productinfo

Type

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.7
VulDB Meta Temp Score: 4.5

VulDB Base Score: 4.7
VulDB Temp Score: 4.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Prototype pollution
CWE: CWE-1321 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: RubyGems 28.3.0

Timelineinfo

11/15/2026 Advisory disclosed
11/15/2026 +0 days CVE reserved
11/15/2026 +0 days VulDB entry created
11/15/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CNA: Gitea
CVE: CVE-2026-118389 (🔒)

GCVE (CVE): GCVE-0-2026-118389
GCVE (VulDB): GCVE-100-437544

Entryinfo

Created: 11/15/2026 22:43
Changes: 11/15/2026 22:43 (55)
Complete: 🔍
Cache ID: 216::103

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