Parse Server vulnerable to session token exfiltration via `redirectClassNameForKey` query parameter
Impact
A vulnerability in Parse Server's query handling allows an authenticated or unauthenticated attacker to exfiltrate session tokens of other users by exploiting the redirectClassNameForKey query parameter. Exfiltrated session tokens can be used to take over user accounts.
The vulnerability requires the attacker to be able to create or update an object with a new relation field, which depends on the Class-Level Permissions of at least one class.
Patches
The fix applies the same security checks that normally protect class access after the query redirect, ensuring that queries redirected via redirectClassNameForKey are subject to the same restrictions as direct queries to the target class.
Workarounds
Set restrictive Class-Level Permissions to prevent clients from creating new fields on classes, specifically by disabling addField for public access and unauthenticated users. Note that this limits client functionality and does not fully eliminate the risk if a relation field pointing to a protected class already exists in the schema.
References
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-6r2j-cxgf-495f
- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.8
- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.21
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | parse-server | >= 9.0.0-alpha.1, < 9.5.2-alpha.8, < 8.6.21 | 9.5.2-alpha.8, 8.6.21 |
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-6r2j-cxgf-495f
- https://nvd.nist.gov/vuln/detail/CVE-2026-30965
- https://github.com/parse-community/parse-server
- https://github.com/parse-community/parse-server/releases/tag/8.6.21
- https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.8
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N- Weakness (CWE)
CWE-863- Platform
- npm
- Package
parse-server- Disclosed
- 11.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-6r2j-cxgf-495f - CC BY 4.0
Vulnerability history: parse-server
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 116
- First → latest
- 06.2019 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 17
- High 49
- Medium 40
- Low 10
Disclosures per year
- 2019: 2
- 2020: 4
- 2021: 4
- 2022: 12
- 2023: 5
- 2024: 4
- 2025: 6
- 2026: 79
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Parse Server vulnerable to session token exfiltration via `redirectClassNameForKey` query parameter this entry
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