CVE-2026-9545
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Summary
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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| curl | curl | 8.11.0 < 8.14.2 | affected |
| curl | curl | 8.15.0 < 8.16.1 | affected |
| curl | curl | 8.17.0 < 8.20.1 | affected |
| curl | curl | 962097b8dd44ed5b9e7984bc1cdffdbdd566857f < 7b9613fa9b1a5e04301a3920eef58e8138dad05e | affected |
| curl | curl | 8.20.0 | affected |
| curl | curl | 8.19.0 | affected |
| curl | curl | 8.18.0 | affected |
| curl | curl | 8.17.0 | affected |
| curl | curl | 8.16.0 | affected |
| curl | curl | 8.15.0 | affected |
| curl | curl | 8.14.1 | affected |
| curl | curl | 8.14.0 | affected |
| curl | curl | 8.13.0 | affected |
| curl | curl | 8.12.1 | affected |
| curl | curl | 8.12.0 | affected |
| curl | curl | 8.11.1 | affected |
| curl | curl | 8.11.0 | affected |
Weaknesses
- CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: poc
- Automatable: yes
- Technical Impact: partial
Additional References
References
- https://curl.se/docs/CVE-2026-9545.json
- https://curl.se/docs/CVE-2026-9545.html
- https://hackerone.com/reports/3752888
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