GHSA-qpc3-fg4j-8hgm BIT-parse-2026-33429 CVE-2026-33429

Parse Server has a protected field change detection oracle via LiveQuery watch parameter

Medium npm

Severity: 0.0 / 10; Medium · CVSS 4.0
Exploit chance (EPSS): 0.33%; Chance of exploitation in the next 30 days. Higher than 26.04% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-203 Observable Discrepancy
Fix: 9.6.0-alpha.43; Upgrade parse-server to this version or later

Description

Impact

An attacker can subscribe to LiveQuery with a watch parameter targeting a protected field. Although the protected field value is properly stripped from event payloads, the presence or absence of update events reveals whether the protected field changed, creating a binary oracle. For boolean protected fields, the timing of change events is equivalent to knowing the field value.

Patches

The watch parameter is now validated against protected fields at subscription time, mirroring the existing validation for the where clause. Subscriptions that include protected fields in watch are rejected with a permission error. Master key connections are exempt.

Workarounds

None.

Affected versions

npm

Package	Vulnerable	Fixed in
parse-server	`>= 9.0.0, < 9.6.0-alpha.43`	`9.6.0-alpha.43`
parse-server	`< 8.6.54`	`8.6.54`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

parse-server npm → `9.6.0-alpha.43`

npm

npm install parse-server@9.6.0-alpha.43

yarn

yarn add parse-server@9.6.0-alpha.43

pnpm

pnpm add parse-server@9.6.0-alpha.43

Severity breakdown

CVSS 4.0 0.0

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

Attack vector: Network
Attack complexity: Low
Attack requirements: Present
Privileges required: None
User interaction: None
Confidentiality (vulnerable system): Low
Integrity (vulnerable system): None
Availability (vulnerable system): None
Confidentiality (subsequent systems): None
Integrity (subsequent systems): None
Availability (subsequent systems): None

CVSS 3.1 5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Weakness

CWE-203: Observable Discrepancy

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

How to prevent it

Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-33429

Packages

github.com/parse-community/parse-server

Timeline

Mar 20, 2026 Published
Jun 17, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-r899-h629-j84r Parse Server vulnerable to stored XSS via malformed Content-Type bypassing file upload extension blocklist	Low	Also affects parse-server
GHSA-97pr-9hgg-3p8r parse-server: LiveQuery discloses object data to a subscriber across an ACL read-access change	Low	Also affects parse-server
GHSA-v8x7-r927-cc93 parse-server: Stored XSS via non-standard file extension bypassing file upload extension blocklist	Low	Also affects parse-server
GHSA-cgxm-vr2f-6fj8 parse-server: Denial of service via exponential-time processing of deeply nested query operators	High	Also affects parse-server
GHSA-wmwx-jr2p-4j4r parse-server: Relation `$relatedTo` query bypasses `protectedFields` and owning-object ACL	Medium	Also affects parse-server
GHSA-75v4-m273-5j49 parse-server: Endpoints `/login` and `/verifyPassword` disclose MFA secrets and protected fields when `_User` get is denied	Medium	Also affects parse-server
GHSA-7wqv-xjf3-x35v parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist	Low	Also affects parse-server
GHSA-p84r-h6rx-f2xr parse-server: Server option routeAllowList is bypassable through batch sub-requests	Medium	Also affects parse-server

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