CVE-2026-9545 (GCVE-0-2026-9545)

Vulnerability from cvelistv5 – Published: 2026-07-03 06:17 – Updated: 2026-07-03 06:17
VLAI
Title
exposing HTTP/3 early data
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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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.
Severity
No CVSS data available.
CWE
Assigner
References
Impacted products
Vendor Product Version
curl curl Affected: 8.20.0 , ≤ 8.20.0 (semver)
Affected: 8.19.0 , ≤ 8.19.0 (semver)
Affected: 8.18.0 , ≤ 8.18.0 (semver)
Affected: 8.17.0 , ≤ 8.17.0 (semver)
Affected: 8.16.0 , ≤ 8.16.0 (semver)
Affected: 8.15.0 , ≤ 8.15.0 (semver)
Affected: 8.14.1 , ≤ 8.14.1 (semver)
Affected: 8.14.0 , ≤ 8.14.0 (semver)
Affected: 8.13.0 , ≤ 8.13.0 (semver)
Affected: 8.12.1 , ≤ 8.12.1 (semver)
Affected: 8.12.0 , ≤ 8.12.0 (semver)
Affected: 8.11.1 , ≤ 8.11.1 (semver)
Affected: 8.11.0 , ≤ 8.11.0 (semver)
Create a notification for this product.
Credits
Eunsoo Kim (Autonomous Code Security team at Microsoft) Stefan Eissing
Show details on NVD website
To clipboard 

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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Detection rules are retrieved from Rulezet.