CURL-CVE-2025-9086

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Source
https://curl.se/docs/CVE-2025-9086.html
Import Source
https://curl.se/docs/CURL-CVE-2025-9086.json
JSON Data
https://api.osv.dev/v1/vulns/CURL-CVE-2025-9086
Aliases
Published
2025-09-10T08:00:00Z
Modified
2026-01-06T09:06:08.915067Z
Summary
Out of bounds read for cookie path
Details
  1. A cookie is set using the secure keyword for https://target
  2. curl is redirected to or otherwise made to speak with http://target (same hostname, but using clear text HTTP) using the same cookie set
  3. The same cookie name is set - but with just a slash as path (path="/"). Since this site is not secure, the cookie should just be ignored.
  4. 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 
{
    "CWE": {
        "id": "CWE-125",
        "desc": "Out-of-bounds Read"
    },
    "www": "https://curl.se/docs/CVE-2025-9086.html",
    "severity": "Low",
    "URL": "https://curl.se/docs/CVE-2025-9086.json",
    "issue": "https://hackerone.com/reports/3294999",
    "affects": "lib",
    "award": {
        "currency": "USD",
        "amount": "505"
    },
    "package": "curl",
    "last_affected": "8.15.0"
}
References
Credits
    • Google Big Sleep - FINDER
    • Daniel Stenberg - REMEDIATION_DEVELOPER

Affected packages

Git / github.com/curl/curl.git

Affected ranges

Type
SEMVER
Events
Introduced
8.13.0
Fixed
8.16.0
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
8.15.0

Database specific

source

"https://curl.se/docs/CURL-CVE-2025-9086.json"

vanir_signatures

[
    {
        "deprecated": false,
        "id": "CURL-CVE-2025-9086-2ce4e7e1",
        "digest": {
            "length": 1784.0,
            "function_hash": "165902635522532233032557057269934243979"
        },
        "source": "https://github.com/curl/curl.git/commit/c6ae07c6a541e0e96d0040afb62b45dd37711300",
        "signature_version": "v1",
        "signature_type": "Function",
        "target": {
            "file": "lib/cookie.c",
            "function": "replace_existing"
        }
    },
    {
        "deprecated": false,
        "id": "CURL-CVE-2025-9086-6c20969f",
        "digest": {
            "length": 322.0,
            "function_hash": "179049927262469336932167202840771014604"
        },
        "source": "https://github.com/curl/curl.git/commit/c6ae07c6a541e0e96d0040afb62b45dd37711300",
        "signature_version": "v1",
        "signature_type": "Function",
        "target": {
            "file": "lib/cookie.c",
            "function": "sanitize_cookie_path"
        }
    },
    {
        "deprecated": false,
        "id": "CURL-CVE-2025-9086-c5a4a9ab",
        "digest": {
            "threshold": 0.9,
            "line_hashes": [
                "314730481499983113609492170489629066758",
                "97889432682566702809081681306452823952",
                "186720809114596896195841790260773946686",
                "333994858511398020049490665140562940015",
                "120410423370335933348745655926364574808",
                "132789178882440746894753449605196926327",
                "144893248242839835308371152775449701347",
                "273384927473139849547348528647818722765",
                "141735703432496355136970257966860936664"
            ]
        },
        "source": "https://github.com/curl/curl.git/commit/c6ae07c6a541e0e96d0040afb62b45dd37711300",
        "signature_version": "v1",
        "signature_type": "Line",
        "target": {
            "file": "lib/cookie.c"
        }
    }
]