Vulnerability details

CVE-2026-27804

parse-community parse-server

Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter

CVSS 4.0
9.3Critical

Official description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.3 and 9.1.1-alpha.4, an unauthenticated attacker can forge a Google authentication token with `alg: "none"` to log in as any user linked to a Google account, without knowing their credentials. All deployments with Google authentication enabled are affected. The fix in versions 8.6.3 and 9.1.1-alpha.4 hardcodes the expected `RS256` algorithm instead of trusting the JWT header, and replaces the Google adapter's custom key fetcher with `jwks-rsa` which rejects unknown key IDs. As a workaround, dsable Google authentication until upgrading is possible.

CVSS scores

ScoreVersionSourceVector
9.3Critical 4.0 CVEProject cvelistV5 (CNA) (GitHub_M) CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Affected products

VendorProductVersionsSource
parse-community parse-server < 8.6.3 CVEProject cvelistV5 (CNA)
parse-community parse-server >= 9.0.0, < 9.3.1-alpha.4 CVEProject cvelistV5 (CNA)

References and advisories

5
Kolun on Telegram @kolunsec Exploited CVEs, key news and a daily digest Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.

Details

Published
2026-02-26
Last updated
2026-02-26
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.2%
Probability of exploitation in 30 days
10%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
None
Technical impact
Total

Weaknesses (CWE)

  • CWE-327
    Use of a Broken or Risky Cryptographic Algorithm
  • CWE-345
    Insufficient Verification of Data Authenticity