CVE-2026-44217: CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') in rexxars sse-channel
sse-channel is an SSE-implementation which can be used to any node.js http request/response stream. Prior to 4.0.1, implementations that allow user-provided values to be passed to event, retry or id fields are susceptible to event spoofing, where an attacker could inject arbitrary messages into the stream. This vulnerability is fixed in 4.0.1.
AI Analysis
Technical Summary
The rexxars sse-channel library, used for server-sent events in Node.js HTTP streams, improperly neutralizes CRLF sequences in user-supplied values for event, retry, or id fields prior to version 4.0.1. This allows attackers to perform CRLF injection, enabling event spoofing by injecting arbitrary messages into the SSE stream. The vulnerability is identified as CWE-93 and has a CVSS 4.0 base score of 6.6 (medium severity). The issue is resolved in version 4.0.1.
Potential Impact
An attacker can inject arbitrary messages into the SSE stream by exploiting improper neutralization of CRLF sequences in user-controlled fields. This can lead to event spoofing, potentially misleading clients consuming the SSE stream. There is no indication of privilege escalation, denial of service, or other impacts beyond event spoofing. No known exploits are currently reported in the wild.
Mitigation Recommendations
Upgrade to sse-channel version 4.0.1 or later, where this vulnerability is fixed. Since the vendor advisory does not provide additional remediation details, applying this official fix is the recommended action. Patch status is confirmed by the version update note in the description.
CVE-2026-44217: CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') in rexxars sse-channel
Description
sse-channel is an SSE-implementation which can be used to any node.js http request/response stream. Prior to 4.0.1, implementations that allow user-provided values to be passed to event, retry or id fields are susceptible to event spoofing, where an attacker could inject arbitrary messages into the stream. This vulnerability is fixed in 4.0.1.
CVSS v4.0
Score 6.6medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The rexxars sse-channel library, used for server-sent events in Node.js HTTP streams, improperly neutralizes CRLF sequences in user-supplied values for event, retry, or id fields prior to version 4.0.1. This allows attackers to perform CRLF injection, enabling event spoofing by injecting arbitrary messages into the SSE stream. The vulnerability is identified as CWE-93 and has a CVSS 4.0 base score of 6.6 (medium severity). The issue is resolved in version 4.0.1.
Potential Impact
An attacker can inject arbitrary messages into the SSE stream by exploiting improper neutralization of CRLF sequences in user-controlled fields. This can lead to event spoofing, potentially misleading clients consuming the SSE stream. There is no indication of privilege escalation, denial of service, or other impacts beyond event spoofing. No known exploits are currently reported in the wild.
Mitigation Recommendations
Upgrade to sse-channel version 4.0.1 or later, where this vulnerability is fixed. Since the vendor advisory does not provide additional remediation details, applying this official fix is the recommended action. Patch status is confirmed by the version update note in the description.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-05T15:13:47.572Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a038bd7cbff5d8610164953
Added to database: 05/12/2026, 20:21:43 UTC
Last enriched: 05/20/2026, 18:42:17 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 73
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