CVE-2025-12642

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Source
https://cve.org/CVERecord?id=CVE-2025-12642
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-12642.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2025-12642
Downstream
Published
2025-11-03T20:17:06.410Z
Modified
2026-07-15T06:01:37.145871Z
Severity
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
[none]
Details

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

References

Affected packages

Git / github.com/lighttpd/lighttpd1.4

Affected ranges

Type
GIT
Repo
https://github.com/lighttpd/lighttpd1.4
Events
Introduced
b2bdd270506b4cad6a571b629e4fa0a01cd24631
Last affected
b2bdd270506b4cad6a571b629e4fa0a01cd24631
Fixed
35cb89c103877de62d6b63d0804255475d77e5e1
Database specific
Show details 
{
    "cpe": "cpe:2.3:a:lighttpd:lighttpd:1.4.80:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "1.4.80"
        },
        {
            "last_affected": "1.4.80"
        }
    ],
    "source": [
        "CPE_STRING",
        "REFERENCES"
    ]
}

Affected versions

1.*
1.4.80
lighttpd-1.*
lighttpd-1.4.80

Database specific

vanir_signatures_modified 
"2026-07-15T06:01:37Z"
vanir_signatures 
[
    {
        "id": "CVE-2025-12642-473a78bc",
        "deprecated": false,
        "signature_type": "Line",
        "signature_version": "v1",
        "digest": {
            "threshold": 0.9,
            "line_hashes": [
                "177279775846748800587473156359973412692",
                "234107947651447384615462498936120486077",
                "302025777481488930004506134913590170429",
                "53861381006875801283685841489596921050"
            ]
        },
        "source": "https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1",
        "target": {
            "file": "src/request.c"
        }
    }
]
source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-12642.json"