CVE-2025-7339on-headers vulnerable to http response header manipulation
- 3.4LowCVSS base score
- 0.21%Exploitation in 30 daysEPSS · top 89% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
Timeline
ID reserved
By openjs
- 10 days later
· 10 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| openjsCNA (assigner) | 3.1 | Low3.4 | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N |
| NVDNVD · Deferred | 3.1 | Low3.4 | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.21% · top 89% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.4.
Affected products
- affected < 1.1.0
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npmon-headersGHSA-76c9-3jph-rj3q (opens in a new tab)
References
References5
- https://github.com/jshttp/on-headers/security/advisories/GHSA-76c9-3jph-rj3q (opens in a new tab)
- https://github.com/jshttp/on-headers/commit/c6e384908c9c6127d18831d16ab0bd96e1231867 (opens in a new tab)
- https://cna.openjsf.org/security-advisories.html (opens in a new tab)
- https://github.com/expressjs/morgan/issues/315 (opens in a new tab)
- https://github.com/jshttp/on-headers/issues/15 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-21784 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-76c9-3jph-rj3q (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-7339)Record last updated .