CVE-2026-6253
5.9 · MEDIUMOverview
CVE-2026-6253 is a medium-severity vulnerability affecting haxx curl. It was published on May 13, 2026 and has a CVSS 3.1 base score of 5.9 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.9, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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
Remediation
Check the references section for vendor advisories and patches from haxx. Update curl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| haxx | curl | >= 7.14.1, < 8.20.0 | Affected |
Frequently Asked Questions
What is CVE-2026-6253?
CVE-2026-6253 is a medium-severity vulnerability affecting haxx curl. It was published on May 13, 2026 and has a CVSS 3.1 base score of 5.9 (MEDIUM).
How severe is CVE-2026-6253?
This vulnerability has a CVSS 3.1 base score of 5.9, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-6253?
Check the references section for vendor advisories and patches from haxx. Update curl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-6253?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-6253 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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