CVE-2026-6253
Medium
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
SeverityMedium
CVSS5.9
Exploit probability—
ProductHaxx Curl
PublishedMay 13, 2026
First seenMay 13, 2026
Weakness typeCWE-522CWE-522
How to fix
Update
- haxx curl8.20.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| haxx curl | 7.14.1 ≤ v < 8.20.0 | 8.20.0 |
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