CVE-2026-6253
proxy credentials leak over redirect-to proxy
Vexday Risk Score
13Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 5.9EPSS 0.6%KEV nãoPoC —Nuclei —Metasploit —Patch —
Lifecycle
13 May 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
curl · curlWant to know if your infrastructure is exposed to this?
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