Security readout for executives and security teams
Plain-English summary
Parse Server deployments using Google login may let an unauthenticated attacker sign in as any user who has a linked Google account. This is an account-takeover issue, not just a data leak. Organizations using Parse Server with Google authentication should treat it as urgent and prioritize upgrade or temporary disablement of Google auth.
Executive priority
High priority. This can allow direct takeover of customer or employee accounts without credentials where Google login is enabled. Patch or disable Google authentication quickly, especially for externally reachable applications.
Technical view
The Google auth adapter trusted JWT header algorithm selection. Before fixed releases, an attacker could provide a forged Google token using alg:"none" and be accepted as a linked Google user. The advisory says the fix hardcodes RS256 and replaces the custom key fetcher with jwks-rsa to reject unknown key IDs. CVSS v4.0 is 9.3 critical.
Likely exposure
Exposure is limited to Parse Server deployments with Google authentication enabled. The source bundle lists affected versions as <8.6.3 and >=9.0.0,<9.3.1-alpha.4, while the description names 9.1.1-alpha.4 as fixed. Validate against the vendor advisory for the exact branch in use.
Exploitation context
The source states exploitation is unauthenticated, network-accessible, low-complexity, and requires no user interaction. No active exploitation is stated in the provided sources, and KEV is false. The impact is account takeover for users linked to Google accounts.
Researcher notes
The public bundle contains a version discrepancy: the description cites fixes in 8.6.3 and 9.1.1-alpha.4, while affected metadata and references point to 9.3.1-alpha.4. Use the GitHub advisory and release tags as authoritative during triage. Avoid assuming exposure if Google auth is not enabled.
Mitigation direction
- Upgrade Parse Server to a vendor-fixed release for your branch.
- If upgrade cannot happen promptly, disable Google authentication temporarily.
- Review the GitHub advisory for branch-specific fixed version guidance.
- Prioritize internet-facing Parse Server applications using Google auth.
Validation and detection
- Inventory Parse Server versions across production, staging, and self-hosted deployments.
- Confirm whether Google authentication is enabled in Parse Server configuration.
- Compare installed versions against the vendor advisory and release notes.
- After remediation, verify Google login still works with legitimate Google tokens only.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-327: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-345: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-27804 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.3 (4.0)
- Known Exploited
- No
- Published
Vector: 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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: 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
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2CVE reference · x_refsource_CONFIRM
- https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7CVE reference · x_refsource_MISC
- https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330CVE reference · x_refsource_MISC
- https://github.com/parse-community/parse-server/releases/tag/8.6.3CVE reference · x_refsource_MISC
- https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use of a Broken or Risky Cryptographic Algorithm
Use of a Broken or Risky Cryptographic Algorithm represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Insufficient Verification of Data Authenticity
Insufficient Verification of Data Authenticity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.