CVE-2026-9545
Description
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transfers, and when it makes a second transfer to the same site it has been
replaced by the attacker's impostor machine - without a valid certificate.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 session
(`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the
`CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might
send off the second request's bytes on that new connection *before* enforcing
the certificate verification failure. Potentially leaking sensitive
information.
Metadata
Severity & Metrics
No CVSS data available.
Affected products (1)
| Vendor | Product | Platform | Versions |
|---|---|---|---|
| curl | curl | — | 8.20.0 ≤ 8.20.0, 8.19.0 ≤ 8.19.0, 8.18.0 ≤ 8.18.0, 8.17.0 ≤ 8.17.0 … |
Weakness (CWE)
| CWE | Source | Description |
|---|---|---|
| — | cna | CWE-200 Exposure of Sensitive Information to an Unauthorized Actor |
References (3)