diff --git a/docs/development/test-vectors.rst b/docs/development/test-vectors.rst
index 5032c5f..f82e00e 100644
--- a/docs/development/test-vectors.rst
+++ b/docs/development/test-vectors.rst
@@ -159,6 +159,8 @@
   cryptography website.
 * ``rapidssl_sha256_ca_g3.pem`` - The intermediate CA that issued the
   ``cryptography.io.pem`` certificate.
+* ``cryptography.io.precert.pem`` - A pre-certificate with the CT poison
+  extension for the cryptography website.
 * ``wildcard_san.pem`` - A leaf certificate issued by a public CA for
   ``langui.sh`` that contains wildcard entries in the SAN extension.
 * ``san_edipartyname.der`` - A DSA certificate from a `Mozilla bug`_
diff --git a/vectors/cryptography_vectors/x509/cryptography.io.precert.pem b/vectors/cryptography_vectors/x509/cryptography.io.precert.pem
new file mode 100644
index 0000000..015225b
--- /dev/null
+++ b/vectors/cryptography_vectors/x509/cryptography.io.precert.pem
@@ -0,0 +1,30 @@
+-----BEGIN CERTIFICATE-----
+MIIFFjCCA/6gAwIBAgISAxx4en3JApUAe8XyIgs7UnrwMA0GCSqGSIb3DQEBCwUA
+MEoxCzAJBgNVBAYTAlVTMRYwFAYDVQQKEw1MZXQncyBFbmNyeXB0MSMwIQYDVQQD
+ExpMZXQncyBFbmNyeXB0IEF1dGhvcml0eSBYMzAeFw0xODA3MjgxMDE1MDJaFw0x
+ODEwMjYxMDE1MDJaMBoxGDAWBgNVBAMTD2NyeXB0b2dyYXBoeS5pbzCCASIwDQYJ
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+wqGu6q/WHVdgnhWARw3GEFJWDn9wkxBAF08CpzhVaEj+iK+Ut/1HBgNYwqI47h7S
+q+qv0G2qklRVUtEM0zYRsp+y/6vivdbFLlPw8VaerbpJN3gLtpVNcGECAwEAAaOC
+AiQwggIgMA4GA1UdDwEB/wQEAwIFoDAdBgNVHSUEFjAUBggrBgEFBQcDAQYIKwYB
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+YzBhMC4GCCsGAQUFBzABhiJodHRwOi8vb2NzcC5pbnQteDMubGV0c2VuY3J5cHQu
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+cyBhbmQgb25seSBpbiBhY2NvcmRhbmNlIHdpdGggdGhlIENlcnRpZmljYXRlIFBv
+bGljeSBmb3VuZCBhdCBodHRwczovL2xldHNlbmNyeXB0Lm9yZy9yZXBvc2l0b3J5
+LzATBgorBgEEAdZ5AgQDAQH/BAIFADANBgkqhkiG9w0BAQsFAAOCAQEAHyAN+pNt
+rCc5z5rEReS9YZ6oDIm1KVECwFiNiCJKzSnpVFmTwi8EGsu62624hmGICP5dGXAt
+s65UVE9Y8MsF+gNUfYj+52GJg5Hhr+WPKdeT609smpM605hG/eMMLff47Ak7w38D
+McnIy7iBp86ji3sJUd8VhWLUtSNMFExBaKvtIHgs5Rjed7zFwKtsO0d0Act+JWDs
+3twpwkMkW5DUAOwt5cTIf0jFl4m3du4V+NF5qFN8JvvwxG2/7HS9p8yEZyaEJZ7l
+56NjF2nMOpJzHLG3VBm9vxhLDjxlwk7+0XIpsswibLsSvpZ+bRISA5I/1fXmt+J9
+n1TNkyEdwzSZgg==
+-----END CERTIFICATE-----