Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.67 and 9.7.0-alpha.11, an attacker can bypass Cloud Function validator access controls by appending "prototype.constructor" to the function name in the URL. When a Cloud Function handler is declared using the function keyword and its validator is a plain object or arrow function, the trigger store traversal resolves the handler through its own prototype chain while the validator store fails to mirror this traversal, causing all access control enforcement to be skipped. This allows unauthenticated callers to invoke Cloud Functions that are meant to be protected by validators such as requireUser, requireMaster, or custom validation logic. This issue has been patched in versions 8.6.67 and 9.7.0-alpha.11.
9.1
cvsscritical
common vulnerability scoring system v3.1. measures intrinsic severity on a 0-10 scale.
epss0.0003
exploitation prediction scoring system. probability this vulnerability will be exploited in the wild in the next 30 days.
kevno
cisa known exploited vulnerabilities catalog. confirmed active exploitation.
CVSS 3.1Common Vulnerability Scoring System v3.1
9.1/ 10
CRITICAL
exploitability
Attack Vector
Network
Attack Vector (AV:N): exploitable remotely over the network — most dangerous. no physical or adjacent access needed.
Attack Complexity
Low
Attack Complexity (AC:L): no special conditions needed. attack can be reliably reproduced.
Privileges Required
None
Privileges Required (PR:N): no authentication needed. any anonymous attacker can exploit this.
User Interaction
None
User Interaction (UI:N): no victim action needed. fully exploitable without user interaction.
impact
Scope
Unchanged
Scope (S:U): impact limited to the vulnerable component.
Confidentiality
High
Confidentiality (C:H): total information disclosure. attacker gains access to all data within the component.
Integrity
High
Integrity (I:H): complete data modification possible. attacker can modify any data.
Availability
None
Availability (A:N): no availability impact.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 4.0Common Vulnerability Scoring System v4.0
9.1/ 10
CRITICAL
exploitability
Attack Vector
Network
Attack Vector (AV:N): exploitable remotely over the network — most dangerous. no physical or adjacent access needed.
Attack Complexity
Low
Attack Complexity (AC:L): no special conditions needed. attack can be reliably reproduced.
Attack Requirements
Present
Attack Requirements (AT:P): requires specific conditions in the target environment.
Privileges Required
None
Privileges Required (PR:N): no authentication needed. any anonymous attacker can exploit this.
User Interaction
None
User Interaction (UI:N): no victim action needed. fully exploitable without user interaction.
vulnerable system impact
Vuln Confidentiality
High
Confidentiality (VC:H): total information disclosure. attacker gains access to all data within the component.
Vuln Integrity
High
Integrity (VI:H): complete data modification possible. attacker can modify any data.
Vuln Availability
None
Availability (VA:N): no availability impact.
subsequent system impact
Sub Confidentiality
None
Subsequent Confidentiality: impact on data confidentiality of downstream/connected systems. Value: N (None)
Sub Integrity
None
Subsequent Integrity: impact on data integrity of downstream/connected systems. Value: N (None)
Sub Availability
None
Subsequent Availability: impact on service availability of downstream/connected systems. Value: N (None)
