CVE-2026-44214: eventsource-encoder encodes events as well-formed EventSource/Server Sent Event (SSE) messages

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MEDIUM 5.8REMOTEUPGRADE

CVE-2026-44214 is a medium-severity flaw (CVSS 5.8) affecting eventsource-encoder. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.8 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 80%)
CISA exploited list	No
Weakness	CWE-93, CWE-113
Published	2026-05-26
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: rexxars

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-26 20:16 UTCPublished CVE record published
2026-07-24 11:10 UTCUpdated Record last modified

rexxars eventsource-encoder UPGRADE

Affected: < 1.0.2

Fixed in: 1.0.2

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls eventsource-encoder

2. UPGRADE to 1.0.2

npm install eventsource-encoder@">=1.0.2"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-44214?

eventsource-encoder: upgrade to 1.0.2. Exact commands for each OS are on this page.

Is CVE-2026-44214 being exploited?

CVE-2026-44214 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-44214 affect?

CVE-2026-44214 affects eventsource-encoder. Severity is medium (CVSS 5.8). 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 c

How urgent is CVE-2026-44214?

Priority 35/100. Public exploit reference; Remotely exploitable, no login, no user action

References

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