CVE-2026-6253

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Source
https://cve.org/CVERecord?id=CVE-2026-6253
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-6253.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-6253
Aliases
Downstream
Related
Published
2026-05-13T08:28:03Z
Modified
2026-09-10T03:47:28Z
Severity
  • 5.9 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
proxy credentials leak over redirect-to proxy
Details

curl might erroneously pass on credentials for a first proxy to a second proxy.

This can happen when the following conditions are true:

  1. curl is setup to use specific different proxies for different URL schemes
  2. the first proxy needs credentials
  3. the second proxy uses no credentials
  4. while using the first proxy (using say http://), curl is asked to follow a redirect to a URL using another scheme (say https://), accessed using a second, different, proxy
Database specific 
{
    "cna_assigner": "curl",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6253.json",
    "unresolved_ranges": [
        {
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                    "last_affected": "7.16.0"
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                },
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                    "introduced": "7.15.0"
                },
                {
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                },
                {
                    "introduced": "7.14.1"
                },
                {
                    "last_affected": "7.14.1"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}
References

Affected packages

Git / github.com/curl/curl

Affected ranges

Type
GIT
Repo
https://github.com/curl/curl
Events
Introduced
6e1a986e0f35cf36618bd88f42e14ea856b6951b
Fixed
6e3f8dc1f173b47de9a68516ce4b95bf25598c2f
Database specific
Show details 
{
    "cpe": "cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "7.14.1"
        },
        {
            "fixed": "8.20.0"
        }
    ],
    "source": "CPE_RANGE"
}

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-6253.json"