GHSA-mh6f-8j2x-4483
Critical severity vulnerability that affects event-stream and flatmap-stream
The NPM package flatmap-stream is considered malicious. A malicious actor added this package as a dependency to the NPM event-stream package in version 3.3.6. Users of event-stream are encouraged to downgrade to the last non-malicious version, 3.3.4, or upgrade to the latest 4.x version.
Users of flatmap-stream are encouraged to remove the dependency entirely.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
What each source reports
GitHub Advisories Score used
Critical severity vulnerability that affects event-stream and flatmap-stream
The NPM package flatmap-stream is considered malicious. A malicious actor added this package as a dependency to the NPM event-stream package in version 3.3.6. Users of event-stream are encouraged to downgrade to the last non-malicious version, 3.3.4, or upgrade to the latest 4.x version.
Users of flatmap-stream are encouraged to remove the dependency entirely.
- Record
GHSA-mh6f-8j2x-4483- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-506
- Updated
- 2026-11-02
OSV
Critical severity vulnerability that affects event-stream and flatmap-stream
The NPM package flatmap-stream is considered malicious. A malicious actor added this package as a dependency to the NPM event-stream package in version 3.3.6. Users of event-stream are encouraged to downgrade to the last non-malicious version, 3.3.4, or upgrade to the latest 4.x version.
Users of flatmap-stream are encouraged to remove the dependency entirely.
- Record
GHSA-mh6f-8j2x-4483- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-506
- Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
event-streamnpm | 3.3.6 to 3.3.6 | 4.0.0 |
flatmap-streamnpm | All versions | None known |
event-streamnpm | 3.3.6 up to 4.0.0 | 4.0.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
GHSA-mh6f-8j2x-4483 is a critical vulnerability (CVSS 9.8) in event-stream, published November 26, 2018. No source lists public exploit code. Fixed in event-stream 4.0.0.