CVE-2026-44214Public exploitNetwork attack vector

SSE event forgery via unsanitized fields

Published May 26, 2026 · Updated May 26, 2026

CRLF injection in rexxars eventsource-encoder before 1.0.2 allows remote attackers to forge SSE fields and browser events. The encodeMessage function in src/encode.ts interpolates event and string id values into output without rejecting CR or LF line terminators. Reachability requires an application to place attacker-controlled data in either field; trusted static values do not expose the injection path.

CVSS severity5.8
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CRLF injection in rexxars eventsource-encoder before 1.0.2 allows remote attackers to forge SSE fields and browser events. The encodeMessage function in src/encode.ts interpolates event and string id values into output without rejecting CR or LF line terminators. Reachability requires an application to place attacker-controlled data in either field; trusted static values do not expose the injection path.

The record

CVE
CVE-2026-44214
Published
May 26, 2026
Updated
May 26, 2026
Vendor
rexxars
Product
eventsource-encoder
Classifications
CWE-93, CWE-113, T1565.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2026CVE publishedPublication date reported by the CVE source.
  2. May 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

rexxars · eventsource-encoderversion=< 1.0.2

Published CVSS scores

5.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')
CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
T1565.002Transmitted Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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