CVE-2025-9086

A cookie is set using the secure keyword for https://target
curl is redirected to or otherwise made to speak with http://target (same hostname, but using clear text HTTP) using the same cookie set
The same cookie name is set - but with only a slash as path (path="/"). Since this site is not secure, the cookie should be ignored.
A bug in the path comparison logic makes curl read outside a heap buffer boundary

The bug either causes a crash or it potentially makes the comparison come to the wrong conclusion and lets the clear-text site override the contents of the secure cookie, contrary to expectations and depending on the memory contents immediately following the single-byte allocation that holds the path.

The presumed and correct behavior would be to plainly ignore the second set of the cookie since it was already set as secure on a secure host so overriding it on an insecure host should not be okay.

Database specific

{
    "cna_assigner": "curl",
    "cwe_ids": [
        "CWE-125"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/9xxx/CVE-2025-9086.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "8.13.0"
                },
                {
                    "fixed": "8.14.2"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}

References

Affected packages

Git / github.com/curl/curl

Affected ranges

Type

GIT

Repo

https://github.com/curl/curl

Events

Introduced

1c3149881769e7bd79b072e48374e4c2b3678b2f

Fixed

11b991232fbcaa88e2b1faecac224416b0001e35

Database specific

Show details

{
    "cpe": "cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "8.13.0"
        },
        {
            "fixed": "8.16.0"
        }
    ],
    "source": "CPE_RANGE"
}

Type: GIT
Repo: https://github.com/curl/curl.git
Events: Introduced

1aea05a6c2699e80c75936d58569851555acd603

Fixed

c6ae07c6a541e0e96d0040afb62b45dd37711300

Affected versions

8.*

8.13.0

8.14.0

8.14.1

Other

curl-8_13_0

curl-8_14_0

curl-8_14_1

curl-8_15_0

Database specific

source

"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-9086.json"

vanir_signatures

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    {
        "deprecated": false,
        "digest": {
            "function_hash": "165902635522532233032557057269934243979",
            "length": 1784
        },
        "id": "CVE-2025-9086-2ce4e7e1",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/curl/curl.git/commit/c6ae07c6a541e0e96d0040afb62b45dd37711300",
        "target": {
            "file": "lib/cookie.c",
            "function": "replace_existing"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "function_hash": "179049927262469336932167202840771014604",
            "length": 322
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        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/curl/curl.git/commit/c6ae07c6a541e0e96d0040afb62b45dd37711300",
        "target": {
            "file": "lib/cookie.c",
            "function": "sanitize_cookie_path"
        }
    },
    {
        "deprecated": false,
        "digest": {
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            ],
            "threshold": 0.9
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        "id": "CVE-2025-9086-c5a4a9ab",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/curl/curl.git/commit/c6ae07c6a541e0e96d0040afb62b45dd37711300",
        "target": {
            "file": "lib/cookie.c"
        }
    }
]

vanir_signatures_modified

"2026-09-30T08:09:52Z"