Get a Demo

Let's Patch It!

Book a short call with one our specialists, we'll walk you through how Endor Patches work, and ask you a few questions about your environment (like your primary programming languages and repository management). We'll also send you an email right after you fill out the form, feel free to reply with any questions you have in advance!

CVE

CVE-2026-27804

Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter
Back to all
CVE

CVE-2026-27804

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

Impact

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.

Patches

The fix 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.

Workarounds

Disable Google authentication until you can upgrade.

References

  • GitHub advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2
  • Fixed in Parse Server 9.3.1-alpha.4: https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4
  • Fixed in Parse Server 8.6.3: https://github.com/parse-community/parse-server/releases/tag/8.6.3

Package Versions Affected

Package Version
patch Availability
No items found.

Automatically patch vulnerabilities without upgrading

Fix Without Upgrading
Detect compatible fix
Apply safe remediation
Fix with a single pull request

CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.3
-
4.0
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
C
H
U
0
-
C
H
U
9.1
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Related Resources

No items found.

References

https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2, https://nvd.nist.gov/vuln/detail/CVE-2026-27804, https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7, https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330, https://github.com/parse-community/parse-server, https://github.com/parse-community/parse-server/releases/tag/8.6.3, https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4

Severity

9.1

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
9.1
EPSS Probability
0.00041%
EPSS Percentile
0.1213%
Introduced Version
9.0.0,9.0.0-alpha.1,4.3.0
Fix Available
9.3.1-alpha.4,8.6.3

Fix Critical Vulnerabilities Instantly

Secure your app without upgrading.
Fix Without Upgrading