nestjs nest up to 11.1.17 SSE Protocol SseStream._transform injection

Summaryinfo

A vulnerability was found in nestjs nest up to 11.1.17. It has been classified as problematic. Affected by this vulnerability is the function SseStream._transform of the component SSE Protocol. Performing a manipulation results in injection. This vulnerability was named CVE-2026-35515. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, was found in nestjs nest up to 11.1.17. This affects the function SseStream._transform of the component SSE Protocol. The manipulation with an unknown input leads to a injection vulnerability. CWE is classifying the issue as CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. This is going to have an impact on integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-35515 since 04/03/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1055 for this issue.

Upgrading to version 11.1.18 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• nestjs

Name

• nest

Version

• 11.1.0
• 11.1.1
• 11.1.2
• 11.1.3
• 11.1.4
• 11.1.5
• 11.1.6
• 11.1.7
• 11.1.8
• 11.1.9
• 11.1.10
• 11.1.11
• 11.1.12
• 11.1.13
• 11.1.14
• 11.1.15
• 11.1.16
• 11.1.17

Website

• Product: https://github.com/nestjs/nest/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion