Security readout for executives and security teams
Plain-English summary
Nuclide’s hhvm-attach deep link handler could accept a malicious hostname value and render attacker-controlled content inside the editor. The CVE says this could potentially be chained to code execution. The issue affects Nuclide before v0.290.0.
Executive priority
Treat this as a legacy developer-tool risk with critical impact if affected installations remain. Prioritize rapid inventory and removal or upgrade, especially on developer workstations that access source code, secrets, or production credentials.
Technical view
CVE-2018-6333 is a CWE-79 sanitization flaw in Nuclide’s hhvm-attach deep link handler. The hostname parameter was not properly sanitized before rendering, allowing HTML or other content to appear in the editor context. The CVSS 3.1 score is 9.8 critical.
Likely exposure
Exposure is likely limited to environments still using Facebook Nuclide versions prior to v0.290.0 with the affected deep link handler available. The source bundle does not identify affected operating systems, package managers, or downstream distributions.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Public CVE text says a malicious URL could render content in the editor context and could potentially be chained to code execution, but provides no exploit details.
Researcher notes
Evidence is sparse beyond the CVE description and linked commit. Validate exposure through version and handler presence rather than exploit testing. Do not assume active exploitation, broader product impact, or specific attack chains without additional vendor or incident evidence.
Mitigation direction
- Inventory Nuclide installations and record exact versions.
- Upgrade or remove Nuclide versions prior to v0.290.0.
- Review the linked Facebook commit for vendor fix context.
- Check vendor guidance before applying compensating controls.
- Prioritize systems where Nuclide handles external deep links.
Validation and detection
- Confirm whether Nuclide is installed on developer workstations.
- Verify installed Nuclide versions are v0.290.0 or newer.
- Check whether hhvm-attach deep links are registered or reachable.
- Review endpoint software inventory for legacy editor plugins.
- Document any affected hosts and remediation status.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2018-6333 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/facebook/nuclide/commit/65f6bbd683404be1bb569b8d1be84b5d4c74a324CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.