Excessive CPU consumption in Reader.ReadResponse in net/textproto
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.
Unbounded allocation when parsing GNU sparse map in archive/tar
tar.Reader does not set a maximum size on the number of sparse region data blocks in GNU tar pax 1.0 sparse files. A maliciously-crafted archive containing a large number of sparse regions can cause a Reader to read an unbounded amount of data from the archive into memory. When reading from a compressed source, a small compressed input can result in large allocations.
Panic when validating certificates with DSA public keys in crypto/x509
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.
Lack of limit when parsing cookies can cause memory exhaustion in net/http
Despite HTTP headers having a default limit of 1MB, the number of cookies that can be parsed does not have a limit. By sending a lot of very small cookies such as "a=;", an attacker can make an HTTP server allocate a large amount of structs, causing large memory consumption.
Insufficient validation of bracketed IPv6 hostnames in net/url
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.
Quadratic complexity when parsing some invalid inputs in encoding/pem
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.
ALPN negotiation error contains attacker controlled information in crypto/tls
When Conn.Handshake fails during ALPN negotiation the error contains attacker controlled information (the ALPN protocols sent by the client) which is not escaped.
Quadratic complexity when checking name constraints in crypto/x509
Due to the design of the name constraint checking algorithm, the processing time of some inputs scale non-linearly with respect to the size of the certificate. This affects programs which validate arbitrary certificate chains.
Excessive CPU consumption in ParseAddress in net/mail
The ParseAddress function constructs domain-literal address components through repeated string concatenation. When parsing large domain-literal components, this can cause excessive CPU consumption.
CrossOriginProtection insecure bypass patterns not limited to exact matches in net/http
When using http.CrossOriginProtection, the AddInsecureBypassPattern method can unexpectedly bypass more requests than intended. CrossOriginProtection then skips validation, but forwards the original request path, which may be served by a different handler without the intended security protections.
Unexpected paths returned from LookPath in os/exec
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.
Incorrect results returned from Rows.Scan in database/sql
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.
Walk/WalkDir in path/filepath susceptible to symlink race
The filepath.Walk and filepath.WalkDir functions are documented as not following symbolic links, but both functions are susceptible to a TOCTOU (time of check/time of use) race condition where a portion of the path being walked is replaced with a symbolic link while the walk is in progress.
Unexpected command execution in untrusted VCS repositories in cmd/go
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.
Inconsistent handling of O_CREATE|O_EXCL on Unix and Windows in os in syscall
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.
Usage of ExtKeyUsageAny disables policy validation in crypto/x509
Calling Verify with a VerifyOptions.KeyUsages that contains ExtKeyUsageAny unintentionally disabledpolicy validation. This only affected certificate chains which contain policy graphs, which are rather uncommon.
Request smuggling due to acceptance of invalid chunked data in net/http
The net/http package improperly accepts a bare LF as a line terminator in chunked data chunk-size lines. This can permit request smuggling if a net/http server is used in conjunction with a server that incorrectly accepts a bare LF as part of a chunk-ext.
HTTP Proxy bypass using IPv6 Zone IDs in golang.org/x/net
Matching of hosts against proxy patterns can improperly treat an IPv6 zone ID as a hostname component. For example, when the NO_PROXY environment variable is set to "*.example.com", a request to "[::1%25.example.com]:80` will incorrectly match and not be proxied.