CVEvulnerability
CVE-2026-6253
5.9 MEDIUM
Official page ↗
- Status
- Modified
- Published
- 2026-05-13
- Last modified
- 2026-09-15
- Assigner
- 2499f714-1537-4658-8207-48ae4bb9eae9
- CVSS 3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
- 5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-522
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
Affected configurations
• haxx curl (>= 7.14.1 < 8.20.0)
Related
Weakness · CWE (1)
- CWE-522 Insufficiently Protected Credentials weakness
References
- https://curl.se/docs/CVE-2026-6253.html Patch, Vendor Advisory
- https://curl.se/docs/CVE-2026-6253.json Vendor Advisory
- https://hackerone.com/reports/3669637 Exploit, Issue Tracking, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/04/29/11 Mailing List, Patch, Third Party Advisory
- https://hackerone.com/reports/3669637 Exploit, Issue Tracking, Third Party Advisory