# CVE-2025-7339

## Summary

- **CVE ID:** CVE-2025-7339
- **Severity:** LOW
- **CVSS Score:** 3.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N)
- **CWE:** CWE-241
- **Published:** Jul 17, 2025
- **Last Modified:** Mar 12, 2026

## 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.

## Affected Products

- jshttp — on-headers (0)

## References

- [CNA](https://github.com/jshttp/on-headers/security/advisories/GHSA-76c9-3jph-rj3q)
- [CNA](https://github.com/jshttp/on-headers/commit/c6e384908c9c6127d18831d16ab0bd96e1231867)
- [CNA](https://cna.openjsf.org/security-advisories.html)
- [CNA](https://github.com/expressjs/morgan/issues/315)
- [CNA](https://github.com/jshttp/on-headers/issues/15)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 7.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._