What’s Vulnerable › Vulnerabilities

CVE-2026-7168: cross-proxy Digest auth state leak

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-13 · updated 2026-09-15
• Weakness: CWE-294

Description

Successfully using libcurl to do a transfer over a specific HTTP proxy (`proxyA`) with **Digest** authentication and then changing the proxy host to a second one (`proxyB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Proxy-Authorization:` header field meant for `proxyA`, to `proxyB`.

Affected products

• curl: from 7.12.0 before 8.20.0 — fixed in 8.20.0

How to fix

Upgrade to a fixed version: curl 8.20.0. Check the vendor advisory for mitigations.

References

• https://curl.se/docs/CVE-2026-7168.html
• https://curl.se/docs/CVE-2026-7168.json
• https://hackerone.com/reports/3697719
• http://www.openwall.com/lists/oss-security/2026/04/29/14
• https://hackerone.com/reports/3697719

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