The Reader.ReadResponse function constructs a response string through repeated string concatenation of lines. When the number of lines in a response is large, this can cause excessive CPU consumption.
Validating certificate chains which contain DSA public keys can cause programs to panic, due to a interface cast that assumes they implement the Equal method. This affects programs which validate arbitrary certificate chains.
When Conn.Handshake fails during ALPN negotiation the error contains attacker controlled information (the ALPN protocols sent by the client) which is not escaped.
The processing time for parsing some invalid inputs scales non-linearly with respect to the size of the input. This affects programs which parse untrusted PEM inputs.
The Parse function permits values other than IPv6 addresses to be included in square brackets within the host component of a URL. RFC 3986 permits IPv6 addresses to be included within the host component, enclosed within square brackets. For example: "http://[::1]/". IPv4 addresses and hostnames must not appear within square brackets. Parse did not enforce this requirement.
If the PATH environment variable contains paths which are executables (rather than just directories), passing certain strings to LookPath ("", ".", and ".."), can result in the binaries listed in the PATH being unexpectedly returned.
Cancelling a query (e.g. by cancelling the context passed to one of the query methods) during a call to the Scan method of the returned Rows can result in unexpected results if other queries are being made in parallel. This can result in a race condition that may overwrite the expected results with those of another query, causing the call to Scan to return either unexpected results from the other query or an error.
The go command may execute unexpected commands when operating in untrusted VCS repositories. This occurs when possibly dangerous VCS configuration is present in repositories. This can happen when a repository was fetched via one VCS (e.g. Git), but contains metadata for another VCS (e.g. Mercurial). Modules which are retrieved using the go command line, i.e. via "go get", are not affected.
os.OpenFile(path, os.O_CREATE|O_EXCL) behaved differently on Unix and Windows systems when the target path was a dangling symlink. On Unix systems, OpenFile with O_CREATE and O_EXCL flags never follows symlinks. On Windows, when the target path was a symlink to a nonexistent location, OpenFile would create a file in that location. OpenFile now always returns an error when the O_CREATE and O_EXCL flags are both set and the target path is a symlink.