CVE-2026-9545
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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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.
- Haxx Curl
- < 8.21.0
- CVSS 3.1
- 7.5 HIGH
- EPSS
- 0.3% (19th percentile)
- NVD status
- Analyzed
- Published
- 2026-07-03
No indexed exploits for CVE-2026-9545 yet
Our index is partial: it proves presence, never absence
No exploit for CVE-2026-9545 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.