Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.52 and 9.6.0-alpha.41, an authentication bypass vulnerability allows an attacker to log in as any user who has linked a third-party authentication provider, without knowing the user's credentials. The attacker only needs to know the user's provider ID to gain full access to their account, including a valid session token. This affects Parse Server deployments where the server option allowExpiredAuthDataToken is set to true. The default value is false. This issue has been patched in versions 8.6.52 and 9.6.0-alpha.41.
CVE-2026-33409
CRITICALNVD 9.19.1Trending — 3 sources updated this week
EchelonGraph scoreLOW confidence
This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: 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.
- CVSS v3
- 9.1
- EG Score
- 9.1(low)
- EG Risk
- 45(Track)EG Risk 45/100SSVC: 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 computedSeverity91% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 37%
- KEV
- Not listed
Published
March 24, 2026
Last Modified
June 17, 2026
Advisory Details (5)
Auto-updated Jul 27, 2026Patch available. Sources: github, github_commit, github_pr.
github Patch Available
Auth provider validation bypass on login via partial authData · Advisory · parse-community/parse-server · GitHub
https://github.com/parse-community/parse-server/security/advisories/GHSA-pfj7-wv7c-22prgithub_pr Patch Available
fix: Auth provider validation bypass on login via partial authData (GHSA-pfj7-wv7c-22pr)
Patch available: parse-community/parse-server 8.6.81 (PR #10247 merged 2026-03-19)
https://github.com/parse-community/parse-server/pull/10247github_pr Patch Available
fix: Auth provider validation bypass on login via partial authData (GHSA-pfj7-wv7c-22pr)
Patch available: parse-community/parse-server 9.9.1-alpha.6 (PR #10246 merged 2026-03-19)
https://github.com/parse-community/parse-server/pull/10246github_commit Patch Available
commit 98f4ba5bcf2c (parse-community/parse-server)
Patch available: parse-community/parse-server 9.9.1-alpha.6 (contains commit 98f4ba5bcf2c)
https://github.com/parse-community/parse-server/commit/98f4ba5bcf2c199bfe6225f672e8edcd08ba732dgithub_commit Patch Available
commit 8d7df5639c4a (parse-community/parse-server)
Patch available: parse-community/parse-server 8.6.81 (contains commit 8d7df5639c4a)
https://github.com/parse-community/parse-server/commit/8d7df5639c4a35768fe8b78b4580b30e8a74721cWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 4× 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.
- 2026-07-30 16:28 UTCEPSS rescore
- 2026-07-30 01:30 UTCEPSS rescore
- 2026-07-27 14:29 UTCEG score recompute
- 2026-07-27 14:27 UTCOSV refresh
Related CVEs(same CWE)
Same CWE
10 shownCWE-287
Frequently asked(5)
What is CVE-2026-33409?
CVE-2026-33409 is a critical vulnerability published on March 24, 2026. Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.52 and 9.6.0-alpha.41, an authentication bypass vulnerability allows an attacker to log in as any user who has linked a third-party authentication provider, without knowing…
When was CVE-2026-33409 disclosed?
CVE-2026-33409 was first published in the National Vulnerability Database on March 24, 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-2026-33409 actively exploited?
CVE-2026-33409 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 62.8% of all scored CVEs.
What is the CVSS score of CVE-2026-33409?
CVE-2026-33409 has a CVSS v3 base score of 9.1 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-33409?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33409, 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
Explore the affected products and dependency analysis for CVE-2026-33409
Is Your Infrastructure Affected by CVE-2026-33409?
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