CVE-2026-6253
proxy credentials leak over redirect-to proxy
- State
- Published
- Severity
- 5.9 Medium
- Published
- May 13, 2026
- Updated
- Sep 15, 2026
- Reserved
- Apr 13, 2026
Description
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
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | CISA-ADP |
Weaknesses
- CWE-522 Insufficiently Protected Credentials
Affected Products
| Product | Versions |
|---|---|
curlcurl |
|
curlcurl |
|
curlcurl |
|
References
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