proto-default skips SSH verification

When a user invokes curl using a schemeless URL combined with --proto-default sftp or scp, a disconnect occurs between the tool layer and libcurl. The tool layer incorrectly infers the URL scheme, which erroneously bypasses the initialization of critical SSH security options like...

WS Auto-PONG memory exhaustion

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages...

exposing HTTP/3 early data

In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate. When libcurl returns to the hostname the second time with a cached SSL...

SASL double-free

The curl logic that works with SASL authentication could end up cleaning up the GSASL context twice without clearing the pointer in between, making it free the same pointer twice...

SASL password overflow via integer overflow

libcurl contains a buffer overrun in the SASL authentication code. The internal function Curlauthcreateplainmessage fails to correctly verify that the passed in lengths for name and password are not too long, then calculates a buffer size to allocate. On systems with a 32-bit sizet, the math to...

URL unescape heap overflow via integer truncation

The URL percent-encoding decode function in libcurl is called curleasyunescape. Internally, even if this function would be made to allocate a destination buffer larger than 2GB, it would return that new length in a signed 32-bit integer variable, thus the length would get either truncated only or...