TI-2026-32193 Aliases CVE-2026-44214 GHSA-m9g3-3g99-mhpx

eventsource-encoder: SSE event injection via unsanitized event and id fields

HIGH 65CWE-113Published 2026-05-26 · Updated 2026-05-27

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

eventsource-encoder encodes events as well-formed EventSource/Server Sent Event (SSE) messages. Prior to 1.0.2, eventsource-encoder does not sanitize the event or id fields of an EventSourceMessage before serializing them. An attacker who controls either field can inject arbitrary Server-Sent Events line terminators (\n, \r, or \r\n) and thereby forge additional SSE fields or entire messages on the stream. This vulnerability is fixed in 1.0.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00277 20th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed eventsource-encoder (rexxars): 1.0.2eventsource-encoder (npm): 1.0.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
rexxars	eventsource-encoder	before 1.0.2	1.0.2	Patch available	CNA
—	eventsource-encoder (npm)	before 1.0.2	1.0.2	Patch available	GHSA-m9g3-3g99-mhpx

eventsource-encoder Vendorrexxars Affected before 1.0.2 Fixed in 1.0.2 Patch available CNA
eventsource-encoder (npm) Vendor— Affected before 1.0.2 Fixed in 1.0.2 Patch available GHSA-m9g3-3g99-mhpx

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:rexxars:eventsource-encoder::::::node.js::*	before 1.0.2	Vulnerable	rexxars

cpe:2.3:a:rexxars:eventsource-encoder:*:*:*:*:*:node.js:*:* Versions before 1.0.2 Vulnerable ·rexxars

Remediation

Fix · CNA eventsource-encoder (rexxars) Fixed in 1.0.2
Fix · GHSA-m9g3-3g99-mhpx eventsource-encoder (npm) Fixed in 1.0.2 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-44214
2026-10-03 Alias added: GHSA-m9g3-3g99-mhpx

References

Exploit 1

https://github.com/rexxars/eventsource-encoder/security/advisories/GHSA-m9g3-3g99-mhpx

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-44214

Other 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences