Vladimir Sitnikov

pgjdbc, the PostgreSQL JDBC Driver, versions 42.7.4 and 42.7.5 can send the previous contents of the GSS send buffer in place of the first part of a value on a connection with GSS encryption (gssEncMode=prefer or require), and the server stores the value without an error. The buffer is 16320 bytes with MIT Kerberos. The stored value then holds bytes of the messages the driver sent just before it on the same connection, such as the statement's SQL text, its other parameters, and earlier rows of the same batch, instead of the bytes the application supplied. Values at least as long as the buffer are affected when the driver writes them from a byte array: bind parameters set with setString, setBytes, or a ByteStreamWriter, CopyIn.writeToCopy, and LargeObject.write. Most such writes fail with an ArrayIndexOutOfBoundsException instead. The default, gssEncMode=allow, does not start GSS encryption, and connections without GSS encryption are not affected. Versions 42.7.3 and earlier are not affected, and 42.7.6 fixes the problem.

pgjdbc, the PostgreSQL JDBC Driver, versions 42.7.4 through 42.7.13 pads a value that is shorter than its declared length with bytes left in its send buffer instead of zeros, and the server stores those bytes as part of the value. The bytes are messages the driver sent earlier on the same connection: SQL text and parameter values of recent statements, which on a pooled connection can come from other requests. Each padded value can carry up to 8192 bytes of this traffic, or 16320 bytes on a connection with GSS encryption. The padding happens when an application declares a length larger than the data it supplies, through PreparedStatement.setObject with a ByteStreamWriter, CopyIn.writeToCopy, PGCopyOutputStream.write, LargeObject.write, or Blob.setBytes. The driver accepts these calls without an error. An attacker who can make the application store such a value and read it back can collect earlier traffic. Applications whose declared lengths always match their data are not affected. Versions 42.7.3 and earlier pad with zeros.