CVE-2026-27804

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 93% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
9.1
EG Score
9.1(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

February 26, 2026

Last Modified

June 17, 2026

Advisory Details (5)

Auto-updated Sep 16, 2026
Patch available. Sources: github_commit, github_release, github.
github Patch Available

Account takeover via JWT algorithm confusion in Google auth adapter · Advisory · parse-community/parse-server · GitHub

https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2
github_release Patch Available

9.3.1-alpha.4

Patch available: parse-community/parse-server 9.3.1-alpha.4 (pre-release)

https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4
github_release Patch Available

8.6.3

Patch available: parse-community/parse-server 8.6.3

https://github.com/parse-community/parse-server/releases/tag/8.6.3
github_commit Patch Available

commit 9d5942d50e55 (parse-community/parse-server)

Patch available: parse-community/parse-server 9.9.1-alpha.13 (contains commit 9d5942d50e55)

https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330
github_commit Patch Available

commit 9b94083accb7 (parse-community/parse-server)

Patch available: parse-community/parse-server 8.6.83 (contains commit 9b94083accb7)

https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
parse-server—8.6.3—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:27 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-13 16:47 UTCEPSS rescore
  7. 2026-09-12 15:01 UTCEPSS rescore
  8. 2026-09-11 14:52 UTCEPSS rescore
  9. 2026-09-10 09:34 UTCEPSS rescore
  10. 2026-09-08 22:00 UTCEPSS rescore
  11. 2026-09-07 16:01 UTCEPSS rescore
  12. 2026-09-06 13:47 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-04 05:06 UTCEPSS rescore
  15. 2026-09-02 14:11 UTCEPSS rescore
  16. 2026-09-01 13:53 UTCEPSS rescore
  17. 2026-09-01 04:39 UTCEPSS rescore
  18. 2026-09-01 04:39 UTCEPSS rescore
  19. 2026-09-01 01:34 UTCOSV refresh
  20. 2026-08-30 19:17 UTCEPSS rescore
  21. 2026-08-30 01:22 UTCEPSS rescore
  22. 2026-08-28 21:41 UTCEPSS rescore
  23. 2026-08-27 14:25 UTCEPSS rescore
  24. 2026-08-26 14:46 UTCEPSS rescore
  25. 2026-08-25 13:48 UTCEPSS rescore
Show 33 more
  1. 2026-08-21 23:49 UTCEPSS rescore
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-19 17:03 UTCEPSS rescore
  4. 2026-08-18 13:48 UTCEPSS rescore
  5. 2026-08-17 13:47 UTCEPSS rescore
  6. 2026-08-16 14:56 UTCEPSS rescore
  7. 2026-08-16 02:14 UTCEPSS rescore
  8. 2026-08-15 01:31 UTCEG score recompute
  9. 2026-08-15 01:30 UTCEPSS rescore
  10. 2026-08-14 08:58 UTCEG score recompute
  11. 2026-08-13 22:00 UTCEPSS rescore
  12. 2026-08-13 00:58 UTCEG score recompute
  13. 2026-08-12 13:50 UTCEPSS rescore
  14. 2026-08-11 23:54 UTCEG score recompute
  15. 2026-08-11 13:42 UTCEPSS rescore
  16. 2026-08-11 06:17 UTCEG score recompute
  17. 2026-08-11 00:00 UTCEPSS rescore
  18. 2026-08-09 13:48 UTCEG score recompute
  19. 2026-08-09 13:46 UTCEPSS rescore
  20. 2026-08-07 20:38 UTCEG score recompute
  21. 2026-08-06 13:46 UTCEPSS rescore
  22. 2026-08-06 02:59 UTCEG score recompute
  23. 2026-08-05 19:17 UTCEPSS rescore
  24. 2026-08-04 15:10 UTCEPSS rescore
  25. 2026-08-04 05:48 UTCEG score recompute
  26. 2026-08-03 10:36 UTCEPSS rescore
  27. 2026-08-02 19:30 UTCEG score recompute
  28. 2026-08-02 02:26 UTCEPSS rescore
  29. 2026-08-01 04:16 UTCEPSS rescore
  30. 2026-07-30 16:27 UTCEPSS rescore
  31. 2026-07-30 01:30 UTCEPSS rescore
  32. 2026-07-28 15:36 UTCEPSS rescore
  33. 2026-07-27 13:34 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-27804?
CVE-2026-27804 is a critical vulnerability published on February 26, 2026. 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…
When was CVE-2026-27804 disclosed?
CVE-2026-27804 was first published in the National Vulnerability Database on February 26, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-27804 actively exploited?
CVE-2026-27804 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 92.6% of all scored CVEs.
What is the CVSS score of CVE-2026-27804?
CVE-2026-27804 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-27804?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-27804, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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