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Parse Server session creation endpoint allows overwriting server-generated session fields

Moderate severity GitHub Reviewed Published Mar 16, 2026 in parse-community/parse-server • Updated Mar 19, 2026

Package

npm parse-server (npm)

Affected versions

>= 9.0.0, < 9.6.0-alpha.17
< 8.6.42

Patched versions

9.6.0-alpha.17
8.6.42

Description

Impact

An authenticated user can overwrite server-generated session fields (sessionToken, expiresAt, createdWith) when creating a session object via POST /classes/_Session. This allows bypassing the server's session expiration policy by setting an arbitrary far-future expiration date. It also allows setting a predictable session token value.

Patches

The session creation endpoint now filters out server-generated fields from user-supplied data, preventing them from being overwritten.

Workarounds

Add a beforeSave trigger on the _Session class to validate and reject or strip any user-supplied values for sessionToken, expiresAt, and createdWith.

References

@mtrezza mtrezza published to parse-community/parse-server Mar 16, 2026
Published to the GitHub Advisory Database Mar 17, 2026
Reviewed Mar 17, 2026
Published by the National Vulnerability Database Mar 18, 2026
Last updated Mar 19, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

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

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(3rd percentile)

Weaknesses

Improperly Controlled Modification of Dynamically-Determined Object Attributes

The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified. Learn more on MITRE.

CVE ID

CVE-2026-32742

GHSA ID

GHSA-5v7g-9h8f-8pgg

Source code

Credits

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