CVE-2026-8927Critical· 9.1▾ AbyssalPoC availableWhen reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates agains…
▾ Abyssal zone — Critical with a public exploit or in-the-wild use
impact 50.1 · 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 Jul 31.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.4%
0.4% → 0.5%
Last analysed / modified upstream
Exploit / PoC code exists
— → 9.1
none → critical
When reusing a libcurl handle for sequential transfers driven by
environment-variable proxy configuration, libcurl fails to clear the proxy
authentication state between requests. Specifically, if the initial transfer
authenticates against proxyA using Digest auth, a subsequent transfer routed
through proxyB erroneously leaks the Proxy-Authorization: header intended
solely for proxyA.
curl >= 7.12.0, < 8.21.0Upgrade past the affected range:
curl 8.21.0Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-11856Critical· 9.8Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongl…
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-2026-8924Critical· 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-2026-9547High· 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-2026-9546High· 7.5A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared
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.