TOCTOU permits root escape on Linux via Root.Chmod in os in internal/syscall/unix
On Linux, if the target of Root.Chmod is replaced with a symlink while the chmod operation is in progress, Chmod can operate on the target of the symlink, even when the target lies outside the root. The Linux fchmodat syscall silently ignores the AT_SYMLINK_NOFOLLOW flag, which Root.Chmod uses to avoid symlink traversal. Root.Chmod checks its target before acting and returns an error if the target is a symlink lying outside the root, so the impact is limited to cases where the target is replaced with a symlink between the check and operation.
During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between the initial handshake and the resumed handshake, the resumed handshake may succeed when it should have failed. This may happen when a user calls Config.Clone and mutates the returned Config, or uses Config.GetConfigForClient. This can cause a client to resume a session with a server that it would not have resumed with during the initial handshake, or cause a server to resume a session with a client that it would not have resumed with during the initial handshake.
Excessive CPU consumption when building archive index in archive/zip
archive/zip uses a super-linear file name indexing algorithm that is invoked the first time a file in an archive is opened. This can lead to a denial of service when consuming a maliciously constructed ZIP archive.
Memory exhaustion in query parameter parsing in net/url
The net/url package does not set a limit on the number of query parameters in a query. While the maximum size of query parameters in URLs is generally limited by the maximum request header size, the net/http.Request.ParseForm method can parse large URL-encoded forms. Parsing a large form containing many unique query parameters can cause excessive memory consumption.
Handshake messages may be processed at the incorrect encryption level in crypto/tls
During the TLS 1.3 handshake if multiple messages are sent in records that span encryption level boundaries (for instance the Client Hello and Encrypted Extensions messages), the subsequent messages may be processed before the encryption level changes. This can cause some minor information disclosure if a network-local attacker can inject messages during the handshake.
Arbitrary file write using cgo pkg-config directive in cmd/go
Building a malicious file with cmd/go can cause can cause a write to an attacker-controlled file with partial control of the file content. The "#cgo pkg-config:" directive in a Go source file provides command-line arguments to provide to the Go pkg-config command. An attacker can provide a "--log-file" argument to this directive, causing pkg-config to write to an attacker-controlled location.
Unexpected code execution when invoking toolchain in cmd/go
Downloading and building modules with malicious version strings can cause local code execution. On systems with Mercurial (hg) installed, downloading modules from non-standard sources (e.g., custom domains) can cause unexpected code execution due to how external VCS commands are constructed. This issue can also be triggered by providing a malicious version string to the toolchain. On systems with Git installed, downloading and building modules with malicious version strings can allow an attacker to write to arbitrary files on the filesystem. This can only be triggered by explicitly providing the malicious version strings to the toolchain and
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.