CVE-2025-7339: on-headers vulnerable to http response header manipulation
CVE-2025-7339 is a vulnerability in on-headers vulnerable to http response header manipulation, rated Low by Microsoft, with a CVSS 3.1 base score of 3.4 (Low). An attacker can exploit it by an attacker with local access, with high privileges and without user interaction. Microsoft has not reported exploitation in the wild. The EPSS model estimates a 0.21% probability of exploitation activity in the next 30 days, higher than 11% of all scored vulnerabilities. Microsoft published it on 16 September 2025 in the July 2025 Patch Tuesday. It affects 1 product in 1 product family (Other).
Key facts
- CVE ID
- CVE-2025-7339
- Severity
- Low CVSS 3.4
- Microsoft severity
- Low
- Exploited in the wild
- No
- Publicly disclosed
- No
- Weakness
- CWE-241
- EPSS
- 0.21% (percentile 11%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- July 2025 Patch Tuesday
- Product families
- Other
CVSS score and vector
Microsoft scores CVE-2025-7339 at 3.4 (temporal 3.4) using CVSS 3.1. Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
| Metric | Value |
|---|---|
| Attack vector | Local |
| Attack complexity | Low |
| Privileges required | High |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | Low |
| Integrity impact | Low |
| Availability impact | None |
Frequently asked questions (Microsoft)
Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Affected products (1)
Other
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| 20124-17086 |
NIST NVD data
- NVD status
- Deferred
- NVD CVSS
- 3.4 (LOW)
- NVD weakness
- CWE-241
- Published to NVD
- NVD last modified
References
- https://cna.openjsf.org/security-advisories.html
- https://github.com/expressjs/morgan/issues/315
- https://github.com/jshttp/on-headers/commit/c6e384908c9c6127d18831d16ab0bd96e1231867
- https://github.com/jshttp/on-headers/issues/15
- https://github.com/jshttp/on-headers/security/advisories/GHSA-76c9-3jph-rj3q
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. | |
| 1.1 | Information published. |