# CVE-2025-9086

## Summary

- **CVE ID:** CVE-2025-9086
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-125
- **Published:** Sep 12, 2025
- **Last Modified:** Sep 15, 2026

## Description

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.

## Affected Products

- curl — curl (8.15.0)
- curl — curl (8.14.1)
- curl — curl (8.14.0)
- curl — curl (8.13.0)
- curl — curl (1aea05a6c2699e80c75936d58569851555acd603)

## References

- [CNA](https://curl.se/docs/CVE-2025-9086.json)
- [CNA](https://curl.se/docs/CVE-2025-9086.html)
- [CNA](https://hackerone.com/reports/3294999)
- [CVE](http://www.openwall.com/lists/oss-security/2025/09/10/1)
- [CVE](https://lists.debian.org/debian-lts-announce/2026/01/msg00002.html)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-089022.html)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-253495.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 1.40%
- **EPSS Percentile:** 71.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._