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GHSA-36xv-jgw5-4q75
No affected components available
Impact
What kind of vulnerability is it? Who is impacted?
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. Spring Framework's own security patch (6e97587) validates these same fields (id, event) for the same reason.
Actual impact:
- Event spoofing: Attacker forges SSE events with arbitrary
event:types, causing client-sideEventSource.addEventListener()callbacks to fire for wrong event types. - Data injection: Attacker injects arbitrary
data:payloads, potentially triggering XSS if the client renders SSE data as HTML without sanitization. - Reconnection corruption: Attacker injects
id:fields, corrupting theLast-Event-IDheader on reconnection, causing the client to miss or replay events. - Attack precondition: Requires the developer to map user-influenced data to the
typeoridfields of SSE messages. Direct HTTP request input does not reach these fields without developer code bridging the gap.
Patches
Has the problem been patched? What versions should users upgrade to?
Patched in @nestjs/core@11.1.18
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information. There is a low impact on the availability of the system.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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