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schannel: enforce Extended Key Usage for custom CA roots#21629

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vszakats wants to merge 1 commit into
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vszakats:sch-eku
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schannel: enforce Extended Key Usage for custom CA roots#21629
vszakats wants to merge 1 commit into
curl:masterfrom
vszakats:sch-eku

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Reported-by: Joshua Rogers (Aisle Research)

Reported-by: Joshua Rogers (Aisle Research)
@vszakats vszakats added TLS Windows Windows-specific labels May 15, 2026
@bagder bagder requested review from Copilot and jay May 15, 2026 12:25

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Pull request overview

Enforces the Server Authentication Extended Key Usage (EKU) when building the certificate chain in the Schannel backend, so that custom CA roots cannot be misused for server-auth purposes without the proper EKU.

Changes:

  • Initialize CERT_CHAIN_PARA.RequestedUsage with USAGE_MATCH_TYPE_AND and the szOID_PKIX_KP_SERVER_AUTH OID before calling CertGetCertificateChain.

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@vszakats vszakats closed this in 3f8f725 May 16, 2026
@vszakats vszakats deleted the sch-eku branch May 16, 2026 09:56
outcast36 pushed a commit to greearb/curl that referenced this pull request Jun 3, 2026
Reported-by: Joshua Rogers (Aisle Research)

Closes curl#21629
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3 participants