CVE-2026-35515

@nestjs/core Improperly Neutralizes Special Elements in Output Used by a Downstream Component ('Injection')

State
Published
Severity
6.3 Medium
Published
Apr 7, 2026
Updated
Apr 7, 2026
Reserved
Apr 3, 2026

Read the record on cve.org

Description

Nest is a framework for building scalable Node.js server-side applications. Prior to 11.1.18, SseStream._transform() interpolates message.type and message.id directly into Server-Sent Events text protocol output without sanitizing newline characters (\r, \n). Since the SSE protocol treats both \r and \n as field delimiters and \n\n as event boundaries, an attacker who can influence these fields through upstream data sources can inject arbitrary SSE events, spoof event types, and corrupt reconnection state. This vulnerability is fixed in 11.1.18.

Scores

CVSSScoreVectorSource
4.06.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:NGitHub_M

Weaknesses

  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Affected Products

ProductVersions
nestnestjs
  • < 11.1.18Affected

References

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