How severe is CVE-2018-14731?

CVE-2018-14731 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2018-14731 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-14731?

CVE-2018-14731 affects Parceljs Parcel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-14731?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-14731 published?

CVE-2018-14731 was published on 2018-09-21 and last updated on 2026-06-17.

CVE-2018-14731

CVE-2018-14731 is a high-severity vulnerability in Parceljs Parcel with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Parceljs Parcel
Published: 2018-09-21
Last modified: 2026-06-17

Description

An issue was discovered in HMRServer.js in Parcel parcel-bundler. Attackers are able to steal developer's code because the origin of requests is not checked by the WebSocket server, which is used for HMR (Hot Module Replacement). Anyone can receive the HMR message sent by the WebSocket server via a ws://127.0.0.1 connection (with a random TCP port number) from any origin. The random port number can be found by connecting to http://127.0.0.1 and reading the "new WebSocket" line in the source code.

Frequently asked questions

What is CVE-2018-14731?: An issue was discovered in HMRServer.js in Parcel parcel-bundler. Attackers are able to steal developer's code because the origin of requests is not checked by the WebSocket server, which is used for HMR (Hot Module Replacement). Anyone can receive the HMR message sent by the WebSocket server via a ws://127.0.0.1 connection (with a random TCP port number) from any origin. The random port number can be found by connecting to http://127.0.0.1 and reading the "new WebSocket" line in the source code.
How severe is CVE-2018-14731?: CVE-2018-14731 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2018-14731 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-14731?: CVE-2018-14731 affects Parceljs Parcel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-14731?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-14731 published?: CVE-2018-14731 was published on 2018-09-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:parceljs:parcel:-:*:*:*:*:*:*:*

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