blog: July 2025 Security Releases (#1994)

Co-authored-by: Linus Unnebäck <[email protected]>
Co-authored-by: Chris de Almeida <[email protected]>
Co-authored-by: Jon Church <[email protected]>

Author: 4 people

_posts/2025-07-31-security-releases.md

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+---
+title: July 2025 Security Releases
+description: Security releases for Multer and On-headers has been published. We recommend that all users upgrade as soon as possible.
+tags: security vulnerabilities
+authors:
+  - name: Ulises Gascón
+    github: UlisesGascon
+---
+
+The Express team has released a new patch version of [Multer](https://www.npmjs.com/package/multer) addressing a high-severity security vulnerability, and a new minor version of [on-headers](https://www.npmjs.com/package/on-headers) addressing a low-severity security vulnerability.
+
+
+{% include admonitions/warning.html 
+content="We recommend upgrading to the latest version of Multer and On-headers immediately to secure your applications."
+%}
+
+The following vulnerabilities have been addressed:
+
+- [High severity vulnerability CVE-2025-7338 in Multer middleware](#high-severity-vulnerability-cve-2025-7338-in-multer-middleware)
+- [Low severity vulnerability CVE-2025-7339 in On-header middleware](#low-severity-vulnerability-cve-2025-7339-in-on-header-middleware)
+
+## High severity vulnerability CVE-2025-7338 in Multer middleware
+
+**[Multer](https://www.npmjs.com/package/multer) versions `>=1.4.4-lts.1` and `<2.0.2` are vulnerable to denial of service via unhandled exception from malformed request.**
+
+This request causes an unhandled exception, leading to a crash of the process.
+
+**Affected versions**: `>=1.4.4-lts.1, <2.0.2`  
+**Patched version**: `2.0.2`
+
+For more details, see [GHSA-fjgf-rc76-4x9p](https://github.com/expressjs/multer/security/advisories/GHSA-fjgf-rc76-4x9p).
+
+## Low severity vulnerability CVE-2025-7339 in On-header middleware
+
+**[On-headers](https://www.npmjs.com/package/on-headers) versions `<1.1.0` is vulnerable to http response header manipulation**
+
+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()`
+
+**Affected versions**: `<1.1.0`  
+**Patched version**: `1.1.0`
+
+For more details, see [GHSA-76c9-3jph-rj3q](https://github.com/jshttp/on-headers/security/advisories/GHSA-76c9-3jph-rj3q).
+
+---
+
+We recommend upgrading to the latest version of Multer and On-headers immediately to secure your applications.