CVE-2025-12642
HTTP Header Smuggling via Trailer Merge
- State
- Published
- Severity
- 6.9 Medium
- Published
- Nov 3, 2025
- Updated
- Nov 3, 2025
- Reserved
- Nov 3, 2025
Description
lighttpd1.4.80 incorrectly merged trailer fields into headers after http request parsing. This behavior can be exploited to conduct HTTP Header Smuggling attacks.
Successful exploitation may allow an attacker to:
* Bypass access control rules * Inject unsafe input into backend logic that trusts request headers * Execute HTTP Request Smuggling attacks under some conditions
This issue affects lighttpd1.4.80
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N | Toreon |
Weaknesses
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Products
| Product | Versions |
|---|---|
lighttpdlighttpd |
|
References
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