What’s Vulnerable › Vulnerabilities
CVE-2026-35515: @nestjs/core Improperly Neutralizes Special Elements in Output Used by a Downstream Component ('Injection')
- Severity: medium (CVSS 6.1 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-04-07 · updated 2026-10-26
- Weakness: CWE-74
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.
Affected products
- nestjs nest: before 11.1.18 — fixed in 11.1.18
How to fix
Upgrade to a fixed version: nestjs nest 11.1.18. Check the vendor advisory for mitigations.
References
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