🛡️ CVE-2026-6253
🟡 CVSS 5.9 — Medium ⚠️ Exploit Public CWE-522 NVD
5.9
CVSS Score
0 Low4 Medium7 High9 Critical10

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

Details

Severity MEDIUM
CVSS Score 5.9
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-522
Public Exploit ⚠️ Yes
Source NVD
Published 2026-05-13
Updated 2026-06-02
Modified 2026-05-14

Affected Packages

Software From version Fixed in
curl 7.14.1 8.20.0
unknown — —

References

Exploit, Issue Tracking, Third Party Advisory https://hackerone.com/reports/3669637
Mailing List, Patch, Third Party Advisory http://www.openwall.com/lists/oss-security/2026/04/29/11
Exploit, Issue Tracking, Third Party Advisory https://hackerone.com/reports/3669637

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