Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Search

GHSA-26pp-8wgv-hjvm

MediumCVSS 5.3 / 10
Published Apr 8, 2026·Last modified Apr 9, 2026
Affected Components(0)

No affected components available

Description

Summary

Cookie names are not validated on the write path when using setCookie(), serialize(), or serializeSigned() to generate Set-Cookie headers.

While certain cookie attributes such as domain and path are validated, the cookie name itself may contain invalid characters.

This results in inconsistent handling of cookie names between parsing (read path) and serialization (write path).

Details

When applications use setCookie(), serialize(), or serializeSigned() with a user-controlled cookie name, invalid values (e.g., containing control characters such as \r or \n) can be used to construct malformed Set-Cookie header values.

For example:

Set-Cookie: legit
X-Injected: evil=value

However, in modern runtimes such as Node.js and Cloudflare Workers, such invalid header values are rejected and result in a runtime error before the response is sent.

As a result, the reported header injection / response splitting behavior could not be reproduced in these environments.

Impact

Applications that pass untrusted input as the cookie name to setCookie(), serialize(), or serializeSigned() may encounter runtime errors due to invalid header values.

In tested environments, malformed Set-Cookie headers are rejected before being sent, and the reported header injection behavior could not be reproduced.

This issue primarily affects correctness and robustness rather than introducing a confirmed exploitable vulnerability.

Risk Scores
Base Score
5.3

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. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the availability of the system.

Threat Intelligence
4.9

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.25%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Browse More

Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard