What’s Vulnerable › Vulnerabilities

CVE-2025-4727: Meteor livedata_server.js Object.assign redos

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-05-15 · updated 2026-06-17
• Weakness: CWE-400

Description

A vulnerability was found in Meteor up to 3.2.1 and classified as problematic. This issue affects the function Object.assign of the file packages/ddp-server/livedata_server.js. The manipulation of the argument forwardedFor leads to inefficient regular expression complexity. The attack may be initiated remotely. The complexity of an attack is rather high. The exploitation is known to be difficult. The exploit has been disclosed to the public and may be used. Upgrading to version 3.2.2 is able to address this issue. The identifier of the patch is f7ea6817b90952baaea9baace2a3b4366fee6a63. It is recommended to upgrade the affected component.

Affected products

• Meteor: before 3.2.2 — fixed in 3.2.2

How to fix

Upgrade to a fixed version: Meteor 3.2.2. Check the vendor advisory for mitigations.

References

• https://github.com/meteor/meteor/commit/f7ea6817b90952baaea9baace2a3b4366fee6a63
• https://github.com/meteor/meteor/issues/13713
• https://github.com/meteor/meteor/pull/13721
• https://github.com/meteor/meteor/releases/tag/release/METEOR%403.2.2
• https://vuldb.com/?ctiid.309029
• https://vuldb.com/?id.309029
• https://vuldb.com/?submit.570441
• https://vuldb.com/?submit.570441

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