CVE-2026-30965: Parse Server vulnerable to session token exfiltration via `redirectClassNameForKey` query parameter

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 1.6%, percentile 75: FIRST’s model estimates a 1.6% chance of exploitation activity in the next 30 days, higher than 75% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes parse-server (npm) >= 9.0.0-alpha.1, < 9.5.2-alpha.8, fixed in 9.5.2-alpha.8; parse-server (npm) < 8.6.21, fixed in 8.6.21. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

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.

Weakness type: CWE-863.

Product: parse-server (npm) · Assigned by: GitHub_M · Published: 2026-03-10

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 1.55% probability of exploitation activity in the next 30 days; percentile 75.

Timeline

• 2026-03-10 — CVE record published by GitHub_M
• 2026-03-11 — CVE record last updated
• 2026-03-11 — GitHub-reviewed advisory GHSA-6r2j-cxgf-495f published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-6r2j-cxgf-495f github.com
2. CVE.org record CVE-2026-30965 cve.org
3. NVD entry CVE-2026-30965 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical npm advisories · Today’s Security Digest