CVE-2026-6253Medium· 5.9▾ TwilightPoC availablecurl 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 nee…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 32.5 · likelihood 0.1 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 15.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.7%
curl might erroneously pass on credentials for a first proxy to a second proxy.
This can happen when the following conditions are true:
http://), curl is asked to follow
a redirect to a URL using another scheme (say https://), accessed using a
second, different, proxycurl >= 7.14.1, < 8.20.0Upgrade past the affected range:
curl 8.20.0Connected by shared product, vendor, weakness, or advisory.
CVE-2026-3783Medium· 5.3When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a redirect to a second URL, curl could leak that token to the second hostname under some circumstances. If the hostname that the first request is re…
CVE-2026-9079Critical· 9.8libcurl had a flaw that when instructed to clear proxy authentication credentials which made it not do so, leaving the old credentials around to get used for subsequent transfers that should not know nor use them.
CVE-2026-8927Critical· 9.1When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests
CVE-2026-8924Critical· 9.1A flaw in curl’s cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Public Suffix List check
CVE-2026-6429Medium· 5.3When asked to both use a `.netrc` file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances.
CVE-2026-7168Medium· 5.3Successfully 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 wr…