VulnerabilityPublished 10 Mar 2026

CVE-2026-30939: parse-server · Prototype Pollution

Affects parse-serverSource CVE Database V5

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Not known to be exploited · CVSS 8.8 High : upgrade to 9.5.1-alpha.2 or 8.6.13 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

8.8High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 9.5.1-alpha.2, 8.6.13

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: High
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: High: There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade parse-server to 9.5.1-alpha.2 or 8.6.13; parse-community/parse-server to 8.6.13.

Affected software

Product	Affected	Fixed in
parse-communityparse-server	Affected >=9.0.0 <9.5.1-alpha.2	Fixed in 9.5.1-alpha.2
parse-communityparse-server	Affected <8.6.13	Fixed in 8.6.13
npmparse-community/parse-server`pkg:npm/parse-community/parse-server`Other threats	Affected <8.6.13	Fixed in 8.6.13

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Organizations should immediately upgrade parse-server to version 8.6.13 or later, or 9.5.1-alpha.2 or later, where the vulnerability is fixed. If immediate upgrade is not feasible, implement network-level protections such as restricting access to Cloud Function endpoints via firewalls or API gateways to trusted IP addresses only. Employ runtime application self-protection (RASP) or web application firewalls (WAFs) that can detect and block requests containing suspicious prototype property names. Review and harden Cloud Function endpoint configurations to reject unexpected or malformed function names. Implement monitoring and alerting for unusual request patterns targeting Cloud Function endpoints to detect potential exploitation attempts early. Conduct thorough testing after patching to ensure no residual issues remain. Finally, maintain an inventory of parse-server deployments and ensure all instances are updated promptly to prevent exploitation.

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 8.6.13 and 9.5.1-alpha.2, an unauthenticated attacker can crash the Parse Server process by calling a Cloud Function endpoint with a prototype property name as the function name. The server recurses infinitely, causing a call stack size error that terminates the process. Other prototype property names bypass Cloud Function dispatch validation and return HTTP 200 responses, even though no such Cloud Functions are defined. The same applies to dot-notation traversal. All Parse Server deployments that expose the Cloud Function endpoint are affected. This vulnerability is fixed in 8.6.13 and 9.5.1-alpha.2.

Impact

This vulnerability primarily enables denial-of-service (DoS) attacks by crashing the parse-server process, resulting in service unavailability. Organizations relying on parse-server for backend services risk disruption of critical applications, potentially affecting user experience and business operations. Since the attack requires no authentication and can be performed remotely, any exposed Cloud Function endpoint is vulnerable to indiscriminate or targeted DoS attempts. This can lead to downtime, loss of revenue, and damage to reputation. Additionally, the bypass of Cloud Function dispatch validation may confuse monitoring systems or be used in more complex attack scenarios, though no direct code execution or data breach is indicated. The wide adoption of parse-server in various industries, especially startups and enterprises using Node.js backends, increases the scope of impact. Without timely patching, attackers can exploit this vulnerability to degrade service reliability and availability at scale.

Summary

The vulnerability identified as CVE-2026-30939 affects parse-community's parse-server, an open-source backend framework for Node.js environments. The flaw is categorized under CWE-1321, relating to improper control of object prototype attribute modifications, commonly known as prototype pollution. In affected versions prior to 8.6.13 and between 9.0.0 and 9.5.1-alpha.2, an attacker can send specially crafted requests to the Cloud Function endpoint using prototype property names as the function name. This triggers infinite recursion within the server's function dispatch mechanism, leading to a call stack overflow and crashing the parse-server process. Furthermore, certain prototype property names bypass the Cloud Function dispatch validation, causing the server to respond with HTTP 200 OK even though no legitimate Cloud Function exists for those names. This behavior can mislead clients and potentially be leveraged in complex attack chains. The vulnerability requires no authentication or user interaction, making it remotely exploitable by any attacker with network access to the Cloud Function endpoint. The root cause lies in inadequate validation and sanitization of input function names, allowing prototype pollution to interfere with the server's internal logic. The issue is resolved in parse-server versions 8.6.13 and 9.5.1-alpha.2 by properly validating function names and preventing prototype property names from being processed. No known exploits are currently reported in the wild, but the high CVSS score of 8.8 reflects the significant risk of denial-of-service attacks against exposed parse-server instances.

CWE-1321Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution) (opens in a new tab)
Variant weakness
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.
Implementation
By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
Architecture and Design
By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
Implementation · Input Validation
When handling untrusted objects, validating using a schema can be used.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Exploiting Incorrectly Configured Access Control Security Levels (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Mar 2026, 17:07 UTC

WeaknessesCWE-1321

Technical details

References

Community reviews

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