CVE-2026-3783Medium· 5.3▾ TwilightPoC availableWhen 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…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 29.2 · 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
0.5%
0.5% → 0.5%
When 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 redirected to has information in the
used .netrc file, with either of the machine or default keywords, curl
would pass on the bearer token set for the first host also to the second one.
curl >= 7.33.0, < 8.19.0Upgrade past the affected range:
curl 8.19.0Connected by shared product, vendor, weakness, or advisory.
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-2026-9547High· 7.4When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server
CVE-2026-8458Medium· 6.5libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services". libcurl features a pool of recent connections so that subsequent requests …
CVE-2026-8286High· 8.1A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.
CVE-2026-1965Medium· 6.5libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection t…
CVE-2025-9086High· 7.51