medium6.1
CVE-2026-35515
@nestjs/core Improperly Neutralizes Special Elements in Output Used by a Downstream Component ('Injection')
Impact
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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @nestjs/core | <= 11.1.17 | 11.1.18 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Nestjs | Nest | before 11.1.18 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/nestjs/nest/security/advisories/GHSA-36xv-jgw5-4q75
- https://github.com/advisories/GHSA-36xv-jgw5-4q75
- https://github.com/nestjs/nest/pull/16686
- https://github.com/nestjs/nest/commit/83558ae774a990a7916141d3abe0b6548ff3a8b2
- https://github.com/nestjs/nest/releases/tag/v11.1.18
- https://nvd.nist.gov/vuln/detail/CVE-2026-35515