CVE-2026-33409Network attack vector

Account takeover via partial authData validation bypass

Published Mar 24, 2026 · Updated Mar 24, 2026

Improper authentication in Parse Server before 8.6.52 and 9.0.0 through 9.6.0-alpha.40 allows remote attackers to take over linked accounts. RestWrite.handleAuthData validated login authData only when it appeared mutated or the option was false, so an ID-only subset bypassed provider token validation. Exploitation requires a known provider ID, a linked target account, and the non-default allowExpiredAuthDataToken setting; success returns a valid session token with that account's access.

CVSS severity7.0
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Parse Server before 8.6.52 and 9.0.0 through 9.6.0-alpha.40 allows remote attackers to take over linked accounts. RestWrite.handleAuthData validated login authData only when it appeared mutated or the option was false, so an ID-only subset bypassed provider token validation. Exploitation requires a known provider ID, a linked target account, and the non-default allowExpiredAuthDataToken setting; success returns a valid session token with that account's access.

The record

CVE
CVE-2026-33409
Published
Mar 24, 2026
Updated
Mar 24, 2026
Vendor
Parse Platform
Product
Parse Server
Classifications
CWE-287, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 8.6.52
  2. Affected versionversion=>= 9.0.0, < 9.6.0-alpha.41

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Parse Platform · Parse Serverversion=< 8.6.52; version=>= 9.0.0, < 9.6.0-alpha.41

Published CVSS scores

9.1GitLab Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
7.0GitHubCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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