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.

Arbitrary file write using cgo pkg-config directive in cmd/go

A discrepancy between how Go and C/C++ comments were parsed allowed for code smuggling into the resulting cgo binary.

Insufficient validation of bracketed IPv6 hostnames in net/url

Panic when validating certificates with DSA public keys in crypto/x509

Quadratic complexity when parsing some invalid inputs in encoding/pem

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.

Parsing a maliciously crafted DER payload could allocate large amounts of memory, causing memory exhaustion.

ALPN negotiation error contains attacker controlled information in crypto/tls

Excessive CPU consumption in Reader.ReadResponse in net/textproto

Excessive resource consumption when printing error string for host certificate validation in crypto/x509

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.

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 does not affect usage of @latest or bare module paths.

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.

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.