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Low

parse-server: Stored XSS via non-standard file extension bypassing file upload extension blocklist

  • Disclosed: 19.06.2026
  • Updated: 11.10.2026 10:22

Impact

Parse Server's default fileUpload.fileExtensions blocklist is intended to prevent uploading files that browsers render as active content (such as HTML and SVG), which can be used to perform stored cross-site scripting (XSS) attacks against other users. The blocklist could be bypassed by uploading a file whose extension is not an exact match of a blocked extension (for example a non-standard or compound extension) together with a dangerous content type. On storage adapters that persist and serve the uploaded content type (such as S3 and GCS), the file is then served with the attacker-supplied content type, enabling stored XSS against users who open the file URL.

This affects the default configuration, in which authenticated users are allowed to upload files. The default GridFS/filesystem adapter sets the X-Content-Type-Options: nosniff response header, which mitigates browser rendering on that adapter, but the upload restriction itself is still bypassed. This is an incomplete-fix follow-up of GHSA-vr5f-2r24-w5hc and GHSA-7wqv-xjf3-x35v.

Patches

The file upload extension validation now also evaluates the request content type against the configured blocklist whenever the filename's extension is not a recognized type. As a result, a dangerous content type can no longer be preserved by uploading a file with a non-standard extension, and such uploads are rejected.

Workarounds

Configure fileUpload.fileExtensions as a strict allowlist of only the file extensions your application needs (for example ["^(png|jpe?g|gif|pdf)$"]) instead of relying on the default blocklist. Additionally, serve uploaded files from a separate domain than the application, so that any executed content is isolated from the application's origin.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package parse-server >= 9.0.0, < 9.9.1-alpha.11, < 8.6.81 9.9.1-alpha.11, 8.6.81

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness (CWE)
CWE-434
Platform
npm
Package
parse-server
Disclosed
19.06.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-v8x7-r927-cc93 - CC BY 4.0

Vulnerability history: parse-server

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (116) in the archive
Total entries
116
First → latest
06.2019 06.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 17
  • High 49
  • Medium 40
  • Low 10

Disclosures per year

Severity:
  1. parse-server: Stored XSS via non-standard file extension bypassing file upload extension blocklist this entry
    Low CVE-2026-55778 >= 9.0.0, < 9.9.1-alpha.11, < 8.6.81 9.9.1-alpha.11, 8.6.81
  2. parse-server: Denial of service via exponential-time processing of deeply nested query operators
    High CVE-2026-57480 >= 9.0.0, < 9.9.1-alpha.12, < 8.6.82 9.9.1-alpha.12, 8.6.82
  3. Parse Server: Pre-authentication denial of service via client version header regex backtracking
    High CVE-2026-47138 >= 9.0.0, < 9.9.1-alpha.1, < 8.6.77 9.9.1-alpha.1, 8.6.77
  4. Parser Server's streaming file download bypasses afterFind file trigger authorization
    High CVE-2026-34784 >= 9.0.0, < 9.7.1-alpha.1, < 8.6.71 9.7.1-alpha.1, 8.6.71
  5. parse-server has GraphQL complexity validator exponential fragment traversal DoS
    High CVE-2026-34573 >= 9.0.0, < 9.7.0-alpha.12, < 8.6.68 9.7.0-alpha.12, 8.6.68
  6. parse-server has cloud function validator bypass via prototype chain traversal
    Critical CVE-2026-34532 >= 9.0.0, < 9.7.0-alpha.11, < 8.6.67 9.7.0-alpha.11, 8.6.67
  7. LiveQuery protected field leak via shared mutable state across concurrent subscribers
    High CVE-2026-34363 >= 9.0.0, < 9.7.0-alpha.9, < 8.6.65 9.7.0-alpha.9, 8.6.65
  8. Parse Server exposes auth data via verify password endpoint
    High CVE-2026-34215 >= 9.0.0, < 9.7.0-alpha.7, < 8.6.63 9.7.0-alpha.7, 8.6.63
  9. Parse Server exposes auth data via /users/me endpoint
    High CVE-2026-33627 >= 9.0.0, < 9.6.0-alpha.55, < 8.6.61 9.6.0-alpha.55, 8.6.61
  10. Parse Server has SQL Injection through aggregate and distinct field names in PostgreSQL adapter
    High CVE-2026-33539 >= 9.0.0, < 9.6.0-alpha.53, < 8.6.59 9.6.0-alpha.53, 8.6.59
  11. Parse Server: Denial of Service via unindexed database query for unconfigured auth providers
    High CVE-2026-33538 >= 9.0.0, < 9.6.0-alpha.52, < 8.6.58 9.6.0-alpha.52, 8.6.58
  12. Parse Server LiveQuery subscription query depth bypass
    High · 7.5 CVE-2026-33508 >= 9.0.0, < 9.6.0-alpha.45, < 8.6.56 9.6.0-alpha.45, 8.6.56
  13. Parse Server has a query condition depth bypass via pre-validation transform pipeline
    High · 7.5 CVE-2026-33498 >= 9.0.0, < 9.6.0-alpha.44, < 8.6.55 9.6.0-alpha.44, 8.6.55
  14. Parse Server's LiveQuery bypasses CLP pointer permission enforcement
    High · 6.5 CVE-2026-33421 >= 9.0.0, < 9.6.0-alpha.42, < 8.6.53 9.6.0-alpha.42, 8.6.53
  15. Parse Server has an auth provider validation bypass on login via partial authData
    High · 9.1 CVE-2026-33409 >= 9.0.0, < 9.6.0-alpha.41, < 8.6.52 9.6.0-alpha.41, 8.6.52
  16. Parse Server leaks protected fields via LiveQuery afterEvent trigger
    High CVE-2026-33163 >= 9.0.0, < 9.6.0-alpha.35, < 8.6.50 9.6.0-alpha.35, 8.6.50
  17. Parse Server's Cloud function dispatch crashes server via prototype chain traversal
    High CVE-2026-32886 >= 9.0.0, < 9.6.0-alpha.24, < 8.6.47 9.6.0-alpha.24, 8.6.47
  18. Parse Server crash via deeply nested query condition operators
    High CVE-2026-32944 >= 9.0.0, < 9.6.0-alpha.21, < 8.6.45 9.6.0-alpha.21, 8.6.45
  19. Parse Server has a stored XSS filter bypass via Content-Type MIME parameter and missing XML extension blocklist entries
    High CVE-2026-32728 >= 9.0.0, < 9.6.0-alpha.15, < 8.6.41 9.6.0-alpha.15, 8.6.41
  20. Parse Server: Account takeover via operator injection in authentication data identifier
    Critical CVE-2026-32248 >= 9.0.0, < 9.6.0-alpha.12, < 8.6.38 9.6.0-alpha.12, 8.6.38
  21. Parse Server's OAuth2 adapter shares mutable state across providers via singleton instance
    Critical CVE-2026-32242 >= 9.0.0, < 9.6.0-alpha.11, < 8.6.37 9.6.0-alpha.11, 8.6.37
  22. Parse Server's MFA recovery codes not consumed after use
    High CVE-2026-31875 >= 9.0.0-alpha.1, < 9.6.0-alpha.7, < 8.6.33 9.6.0-alpha.7, 8.6.33
  23. Parse Server has a protected fields bypass via dot-notation in query and sort
    High CVE-2026-31872 >= 9.0.0-alpha.1, < 9.6.0-alpha.6, < 8.6.32 9.6.0-alpha.6, 8.6.32
  24. Parse Server vulnerable to SQL Injection via dot-notation sub-key name in `Increment` operation on PostgreSQL
    Critical CVE-2026-31871 >= 9.0.0-alpha.1, < 9.6.0-alpha.5, < 8.6.31 9.6.0-alpha.5, 8.6.31
  25. Parse Server vulnerable to SQL injection via `Increment` operation on nested object field in PostgreSQL
    Critical CVE-2026-31856 >= 9.0.0-alpha.1, < 9.6.0-alpha.3, < 8.6.29 9.6.0-alpha.3, 8.6.29
  26. Parse Server: Classes `_GraphQLConfig` and `_Audience` master key bypass via generic class routes
    High CVE-2026-31800 >= 9.0.0-alpha.1, < 9.5.2-alpha.12, < 8.6.25 9.5.2-alpha.12, 8.6.25
  27. Parse Server OAuth2 authentication adapter account takeover via identity spoofing
    High CVE-2026-30967 >= 9.0.0-alpha.1, < 9.5.2-alpha.9, < 8.6.22 9.5.2-alpha.9, 8.6.22
  28. Parse Server has role escalation and CLP bypass via direct `_Join` table write
    Critical · 10.0 CVE-2026-30966 >= 9.0.0-alpha.1, < 9.5.2-alpha.7, < 8.6.20 9.5.2-alpha.7, 8.6.20
  29. Parse Server vulnerable to session token exfiltration via `redirectClassNameForKey` query parameter
    Critical CVE-2026-30965 >= 9.0.0-alpha.1, < 9.5.2-alpha.8, < 8.6.21 9.5.2-alpha.8, 8.6.21
  30. Parse Server has a protected fields bypass via logical query operators
    High CVE-2026-30962 >= 9.0.0, < 9.5.2-alpha.6, < 8.6.19 9.5.2-alpha.6, 8.6.19
  31. Parse Server missing audience validation in Keycloak authentication adapter
    High CVE-2026-30949 >= 9.0.0, < 9.5.2-alpha.5, < 8.6.18 9.5.2-alpha.5, 8.6.18
  32. Parse Server vulnerable to stored cross-site scripting (XSS) via SVG file upload
    High CVE-2026-30948 >= 9.0.0, < 9.5.2-alpha.4, < 8.6.17 9.5.2-alpha.4, 8.6.17
  33. Parse Server has a bypass of class-level permissions in LiveQuery
    High CVE-2026-30947 >= 9.0.0, < 9.5.2-alpha.3, < 8.6.16 9.5.2-alpha.3, 8.6.16
  34. Parse Server affected by denial-of-service via unbounded query complexity in REST and GraphQL API
    High CVE-2026-30946 < 8.6.15, >= 9.0.0, < 9.5.2-alpha.2 8.6.15, 9.5.2-alpha.2
  35. Parse Server has a NoSQL injection via token type in password reset and email verification endpoints
    High CVE-2026-30941 >= 9.0.0, < 9.5.2-alpha.1, < 8.6.14 9.5.2-alpha.1, 8.6.14
  36. Parse Server: SQL injection via dot-notation field name in PostgreSQL
    Critical CVE-2026-31840 >= 9.0.0, < 9.6.0-alpha.2, < 8.6.28 9.6.0-alpha.2, 8.6.28
  37. Parse Server has Denial of Service (DoS) and Cloud Function Dispatch Bypass via Prototype Chain Resolution
    High CVE-2026-30939 < 8.6.13, >= 9.0.0-alpha.1, < 9.5.1-alpha.2 8.6.13, 9.5.1-alpha.2
  38. Parse Server has Regular Expression Denial of Service (ReDoS) via `$regex` query in LiveQuery
    High CVE-2026-30925 >= 9.0.0-alpha.1, < 9.5.0-alpha.14, < 8.6.11 9.5.0-alpha.14, 8.6.11
  39. Parse Server: JWT audience validation bypass in Google, Apple, and Facebook authentication adapters
    Critical CVE-2026-30863 >= 9.0.0-alpha.1, < 9.5.0-alpha.11, < 8.6.10 9.5.0-alpha.11, 8.6.10
  40. parse-server's endpoint `/loginAs` allows `readOnlyMasterKey` to gain full read and write access as any user
    High CVE-2026-30229 < 8.6.6, >= 9.0.0, < 9.5.0-alpha.4 8.6.6, 9.5.0-alpha.4
Show more (20) Showing 40 of 67

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