CVE-2026-44214

medium

Published 2026-05-26 · Modified 2026-05-28

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CVSS v3

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v4 NEW

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not yet in upstream

VIR risk

5.3

Description

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.

Predictions

Exploit likelihood

63%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

Package impact

Ecosystem	Package	Vulnerable	Fixed
npm	eventsource-encoder	`<1.0.2`	`1.0.2`
NPM	eventsource-encoder	`<= 1.0.1`	`1.0.2`

Application impact

Vendor	Product	Versions	Fixed
rexxars	eventsource-encoder	`{"endExcluding":"1.0.2"}`	`1.0.2`

References

CWEs

CWE-93 CWE-113

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.