Security Vulnerabilities
When performing transfers via libcurl’s multi interface, pooled TLS
connections can outlive their originating easy handles. In OpenSSL 3 provider
configurations, libcurl attaches an allocated library context to the easy
handle's state and passes it to OpenSSL without acquiring an ownership
reference; destroying the easy handle prematurely frees this context while the
active connection retains a dangling pointer, leading to a heap-use-after-free
upon subsequent I/O or post-handshake operations.
CVSS Score
7.5
EPSS Score
0.009
Published
2026-09-06
When `CURLOPT_PINNEDPUBLICKEY` is configured alongside options that disable
standard peer verification (`CURLOPT_SSL_VERIFYPEER = 0` and
`CURLOPT_SSL_VERIFYHOST = 0`), libcurl fails to enforce public key pinning on
connections established without a presented server certificate. Bypassing the
pinning check under these disabled-verification conditions allows
unauthenticated connections to succeed when they should be rejected.
CVSS Score
7.5
EPSS Score
0.006
Published
2026-09-06
A flaw in libcurl makes it wrongly reuse an existing HTTPS connection setup
for a given hostname even when using a different Native CA Store setting
(`CURLSSLOPT_NATIVE_CA`) than when the connection was created.
CVSS Score
7.5
EPSS Score
0.009
Published
2026-09-06
A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of
space (ascii code 32) immediately before the `Secure` attribute causes curl to
store the cookie without its Secure flag. The cookie might then wrongfully be
sent over plaintext HTTP on subsequent requests to the same host.
CVSS Score
7.5
EPSS Score
0.007
Published
2026-09-06
With the wolfSSL backend, when CA caching is enabled and an
`CURLOPT_SSL_CTX_FUNCTION` callback replaces the trust store, libcurl can
silently reinstall the cached store after the callback returns. A certificate
trusted by the cached store but rejected by the callback-selected store is
then incorrectly accepted.
CVSS Score
7.5
EPSS Score
0.004
Published
2026-09-06
When libpsl support is enabled, libcurl fails to enforce the Public Suffix
List boundary check when processing a `Set-Cookie` header where the `Domain`
attribute explicitly matches an origin host that is itself a public suffix
(e.g., `Domain=co.uk` set by `co.uk`).
Instead of coercing it into a strict host-only cookie, libcurl saves the
cookie with wildcard domain scope (`.co.uk`). Consequently, the cookie is
inappropriately included in subsequent outbound requests or HTTP redirects to
arbitrary sibling subdomains under the same public suffix (e.g.,
`attacker.co.uk`).
CVSS Score
8.2
EPSS Score
0.005
Published
2026-09-06
A flaw in libcurl's handling of HTTP/2 Server Push streams, when the parent
handle is set to share connections with other handles, can lead to
use-after-free in the cleanup process.
CVSS Score
9.1
EPSS Score
0.009
Published
2026-09-06
A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given
hostname using Negotiate authentication, when the initial request is done
using empty credentials. This can make user B's request get sent over user A's
previously authenticated connection.
CVSS Score
9.8
EPSS Score
0.012
Published
2026-09-06
A flaw in the libcurl SASL negotiation for LDAP authentication allows an
incomplete handshake sequence to be misinterpreted as a successful
cryptographic verification. An attacker executing a Man-in-the-Middle (MITM)
attack can inject a premature or shortcut response that bypasses complete peer
validation.
CVSS Score
7.4
EPSS Score
0.006
Published
2026-09-06
CVE-2026-86218
N-central is vulnerable to a pre-auth remote code execution This issue affects N-central: before 2026.3.1.14.
Known exploited
CVSS Score
10.0
EPSS Score
0.007
Published
2026-09-06