How severe is CVE-2025-4727?

No CVSS score has been assigned to CVE-2025-4727 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-4727?

CVE-2025-4727 affects the following packages: meteor (npm). Ecosystems affected: npm.

How do I fix CVE-2025-4727?

The records we use list no patched version of meteor for CVE-2025-4727. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

How do I detect CVE-2025-4727 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for meteor, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-4727 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2025-4727 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-4727 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-4727?

CVE-2025-4727 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 60th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-4727?

CVE-2025-4727 is classified as Uncontrolled Resource Consumption (CWE-400), CWE-1333 (CWE-1333). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-4727 published, and has it been updated?

CVE-2025-4727 was published on May 15, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-4727: meteor

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-4727.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk+0.05%

Lower risk than most CVEs60th percentile — riskier than 60% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

meteornpm

2Kdownloads / week

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 Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
📦npm	`meteor`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

meteormeteor

< 3.2.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for meteor, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of meteor for CVE-2025-4727. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

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 r

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CVE-2025-4727 — meteor