CVE-2025-7339 on-headers vulnerable to http response header manipulation
An attacker can manipulate HTTP response headers by passing an array to writeHead, potentially altering application behavior or security controls.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-7339?
CVE-2025-7339 is a low-severity vulnerability in jshttp on-headers, published on 17 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
on-headers is a node.js middleware for listening to when a response writes headers. A bug in on-headers versions `<1.1.0` may result in response headers being inadvertently modified when an array is passed to `response.writeHead()`. Users should upgrade to version 1.1.0 to receive a patch. Uses are strongly encouraged to upgrade to `1.1.0`, but this issue can be worked around by passing an object to `response.writeHead()` rather than an array.
Weakness: CWE-241
Which versions are affected by CVE-2025-7339?
2 open source packages ship an affected version, including on-headers.
| Package | Affected | Fixed in |
|---|---|---|
on-headers npm | All versions | 1.1.0 |
on-headers npm | All versions | 1.1.0 |
How do I fix CVE-2025-7339?
Upgrade on-headers to 1.1.0 or later.
Is CVE-2025-7339 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-7339 exists.
Sources
Also known as CLEANSTART-2026-DT32496, CLEANSTART-2026-KX85997, CLSA-2026-1774916715, DEBIAN-CVE-2025-7339, GHSA-76c9-3jph-rj3q, MINI-2rrj-rgvv-662x and 2 more.