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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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.
References (3)
Core 3
Core References
Scores
CVSS v3
7.5
EPSS
0.0041
EPSS Percentile
32.9%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
yes
Technical Impact
partial
Details
Status
published
Products (14)
curl/curl
8.11.0
curl/curl
8.11.1
curl/curl
8.12.0
curl/curl
8.12.1
curl/curl
8.13.0
curl/curl
8.14.0
curl/curl
8.14.1
curl/curl
8.15.0
curl/curl
8.16.0
curl/curl
8.17.0
... and 4 more
Published
Jul 03, 2026
Tracked Since
Jul 03, 2026