CVE-2026-11856Critical· 9.8▾ AbyssalPoC availableSuccessfully 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…
▾ Abyssal zone — Critical with a public exploit or in-the-wild use
impact 53.9 · 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 4.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.3%
0.3% → 1.1%
Last analysed / modified upstream
Exploit / PoC code exists
— → 9.8
none → critical
Successfully 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 wrongly pass on the Authorization: header field meant for hostA,
to hostB.
curl >= 7.10.6, < 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-2026-7168Medium· 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…
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-2026-6276High· 7.5Using libcurl, when a custom `Host:` header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom `Host:` header set, the second request would use stale information…
CVE-2026-5773High· 7.5libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connectio…
CVE-2026-6253Medium· 5.9curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1
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…