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CVE-2026-34373NVD status: Analyzed

parse-server: Origin Validation Error

CVE-2026-34373 is a high-severity origin validation error vulnerability in parse-server from Parse-community, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected parse-server versions: < 8.6.66; >= 9.0.0, < 9.7.0-alpha.10. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.21% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of parse-server you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  4. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Parse-communityparse-server< 8.6.66; >= 9.0.0, < 9.7.0-alpha.10Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.05.3MediumCNA (github.com)
CVSS 3.18.8HighNVD

Official description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.66 and 9.7.0-alpha.10, the GraphQL API endpoint does not respect the allowOrigin server option and unconditionally allows cross-origin requests from any website. This bypasses origin restrictions that operators configure to control which websites can interact with the Parse Server API. The REST API correctly enforces the configured allowOrigin restriction. This issue has been patched in versions 8.6.66 and 9.7.0-alpha.10.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Origin Validation Error

The product does not properly verify that the source of data or communication is valid.

More Origin Validation Error vulnerabilities (CWE-346)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in parse-server

All parse-server vulnerabilities

Recent Origin Validation Error vulnerabilities

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