yayson up to 4.2.0 Deserialization Logic Store.sync Type prototype pollution

CVSS Meta Temp Score
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CTI Interest Score
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7.0$0-$5k1.22+

Summaryinfo

A vulnerability, which was classified as critical, has been found in yayson up to 4.2.0. Affected by this issue is the function Store.sync of the component Deserialization Logic. The manipulation of the argument Type leads to prototype pollution. This vulnerability is traded as CVE-2026-61534. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in yayson up to 4.2.0. It has been rated as critical. This issue affects the function Store.sync of the component Deserialization Logic. The manipulation of the argument type with an unknown input leads to a prototype pollution vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability.

The identification of this vulnerability is CVE-2026-61534. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

Upgrading to version 4.3.0 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
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: yayson 4.3.0

Timelineinfo

09/12/2026 Advisory disclosed
09/12/2026 +0 days VulDB entry created
09/12/2026 +0 days VulDB entry last update

Sourcesinfo

Status: Confirmed

CVE: CVE-2026-61534 (🔒)
GCVE (CVE): GCVE-0-2026-61534
GCVE (VulDB): GCVE-100-403019

Entryinfo

Created: 09/12/2026 03:24
Changes: 09/12/2026 03:24 (51)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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