How severe is CVE-2018-6333?

CVE-2018-6333 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-6333 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-6333?

CVE-2018-6333 affects Facebook Nuclide. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-6333?

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

When was CVE-2018-6333 published?

CVE-2018-6333 was published on 2018-12-31 and last updated on 2026-06-17.

CVE-2018-6333

CVE-2018-6333 is a critical-severity vulnerability in Facebook Nuclide with a CVSS 3.x base score of 9.8. 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-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Facebook Nuclide
Published: 2018-12-31
Last modified: 2026-06-17

Description

The hhvm-attach deep link handler in Nuclide did not properly sanitize the provided hostname parameter when rendering. As a result, a malicious URL could be used to render HTML and other content inside of the editor's context, which could potentially be chained to lead to code execution. This issue affected Nuclide prior to v0.290.0.

Frequently asked questions

What is CVE-2018-6333?: The hhvm-attach deep link handler in Nuclide did not properly sanitize the provided hostname parameter when rendering. As a result, a malicious URL could be used to render HTML and other content inside of the editor's context, which could potentially be chained to lead to code execution. This issue affected Nuclide prior to v0.290.0.
How severe is CVE-2018-6333?: CVE-2018-6333 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-6333 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-6333?: CVE-2018-6333 affects Facebook Nuclide. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-6333?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-6333 published?: CVE-2018-6333 was published on 2018-12-31 and last updated on 2026-06-17.

References

https://github.com/facebook/nuclide/commit/65f6bbd683404be1bb569b8d1be84b5d4c74a324

Affected products (1)

cpe:2.3:a:facebook:nuclide:*:*:*:*:*:*:*:*

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