Programs which compile regular expressions from untrusted sources may be vulnerable to memory exhaustion or denial of service. The parsed regexp representation is linear in the size of the input, but in some cases the constant factor can be as high as 40,000, making relatively small regexps consume much larger amounts of memory. After fix, each regexp being parsed is limited to a 256 MB memory footprint. Regular expressions whose representation would use more space than that are rejected. Normal use of regular expressions is unaffected.

A maliciously crafted HTTP/2 stream could cause excessive CPU consumption in the HPACK decoder, sufficient to cause a denial of service from a small number of small requests.

A denial of service is possible from excessive resource consumption in net/http and mime/multipart. Multipart form parsing with mime/multipart.Reader.ReadForm can consume largely unlimited amounts of memory and disk files. This also affects form parsing in the net/http package with the Request methods FormFile, FormValue, ParseMultipartForm, and PostFormValue. ReadForm takes a maxMemory parameter, and is documented as storing "up to maxMemory bytes +10MB (reserved for non-file parts) in memory". File parts which cannot be stored in memory are stored on disk in temporary files. The unconfigurable 10MB reserved for non-file parts is excessively large and can potentially open a denial of service vector on its own. However, ReadForm did not properly account for all memory consumed by a parsed form, such as map entry overhead, part names, and MIME headers, permitting a maliciously crafted form to consume well over 10MB. In addition, ReadForm contained no limit on the number of disk files created, permitting a relatively small request body to create a large number of disk temporary files. With fix, ReadForm now properly accounts for various forms of memory overhead, and should now stay within its documented limit of 10MB + maxMemory bytes of memory consumption. Users should still be aware that this limit is high and may still be hazardous. In addition, ReadForm now creates at most one on-disk temporary file, combining multiple form parts into a single temporary file. The mime/multipart.File interface type's documentation states, "If stored on disk, the File's underlying concrete type will be an *os.File.". This is no longer the case when a form contains more than one file part, due to this coalescing of parts into a single file. The previous behavior of using distinct files for each form part may be reenabled with the environment variable GODEBUG=multipartfiles=distinct. Users should be aware that multipart.ReadForm and the http.Request methods that call it do not limit the amount of disk consumed by temporary files. Callers can limit the size of form data with http.MaxBytesReader.

The x/text package before 0.3.3 for Go has a vulnerability in encoding/unicode that could lead to the UTF-16 decoder entering an infinite loop, causing the program to crash or run out of memory. An attacker could provide a single byte to a UTF16 decoder instantiated with UseBOM or ExpectBOM to trigger an infinite loop if the String function on the Decoder is called, or the Decoder is passed to golang.org/x/text/transform.String.

Infinite loop in Read in crypto/rand before Go 1.17.11 and Go 1.18.3 on Windows allows attacker to cause an indefinite hang by passing a buffer larger than 1 << 32 - 1 bytes.

Uncontrolled recursion in Reader.Read in compress/gzip before Go 1.17.12 and Go 1.18.4 allows an attacker to cause a panic due to stack exhaustion via an archive containing a large number of concatenated 0-length compressed files.

In net/http in Go before 1.18.6 and 1.19.x before 1.19.1, attackers can cause a denial of service because an HTTP/2 connection can hang during closing if shutdown were preempted by a fatal error.

Uncontrolled recursion in Decoder.Skip in encoding/xml before Go 1.17.12 and Go 1.18.4 allows an attacker to cause a panic due to stack exhaustion via a deeply nested XML document.

The generic P-256 feature in crypto/elliptic in Go before 1.17.9 and 1.18.x before 1.18.1 allows a panic via long scalar input.

The golang.org/x/crypto/ssh package before 0.0.0-20220314234659-1baeb1ce4c0b for Go allows an attacker to crash a server in certain circumstances involving AddHostKey.

regexp.Compile in Go before 1.16.15 and 1.17.x before 1.17.8 allows stack exhaustion via a deeply nested expression.

Rat.SetString in math/big in Go before 1.16.14 and 1.17.x before 1.17.7 has an overflow that can lead to Uncontrolled Memory Consumption.

An attacker may cause an HTTP/2 endpoint to read arbitrary amounts of header data by sending an excessive number of CONTINUATION frames. Maintaining HPACK state requires parsing and processing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed MaxHeaderBytes, no memory is allocated to store the excess headers, but they are still parsed. This permits an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data, all associated with a request which is going to be rejected. These headers can include Huffman-encoded data which is significantly more expensive for the receiver to decode than for an attacker to send. The fix sets a limit on the amount of excess header frames we will process before closing a connection.

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

An attacker may cause a denial of service by crafting an Accept-Language header which ParseAcceptLanguage will take significant time to parse.

Uncontrolled recursion in Decoder.Decode in encoding/gob before Go 1.17.12 and Go 1.18.4 allows an attacker to cause a panic due to stack exhaustion via a message which contains deeply nested structures.

Uncontrolled recursion in Glob in io/fs before Go 1.17.12 and Go 1.18.4 allows an attacker to cause a panic due to stack exhaustion via a path which contains a large number of path separators.

Certificate.Verify in crypto/x509 in Go 1.18.x before 1.18.1 can be caused to panic on macOS when presented with certain malformed certificates. This allows a remote TLS server to cause a TLS client to panic.

Go before 1.12.11 and 1.3.x before 1.13.2 can panic upon an attempt to process network traffic containing an invalid DSA public key. There are several attack scenarios, such as traffic from a client to a server that verifies client certificates.

net/http in Go before 1.16.12 and 1.17.x before 1.17.5 allows uncontrolled memory consumption in the header canonicalization cache via HTTP/2 requests.

A malicious HTTP/2 client which rapidly creates requests and immediately resets them can cause excessive server resource consumption. While the total number of requests is bounded by the http2.Server.MaxConcurrentStreams setting, resetting an in-progress request allows the attacker to create a new request while the existing one is still executing. With the fix applied, HTTP/2 servers now bound the number of simultaneously executing handler goroutines to the stream concurrency limit (MaxConcurrentStreams). New requests arriving when at the limit (which can only happen after the client has reset an existing, in-flight request) will be queued until a handler exits. If the request queue grows too large, the server will terminate the connection. This issue is also fixed in golang.org/x/net/http2 for users manually configuring HTTP/2. The default stream concurrency limit is 250 streams (requests) per HTTP/2 connection. This value may be adjusted using the golang.org/x/net/http2 package; see the Server.MaxConcurrentStreams setting and the ConfigureServer function.

The x/crypto/ssh package before 0.0.0-20211202192323-5770296d904e of golang.org/x/crypto allows an attacker to panic an SSH server.

ImportedSymbols in debug/macho (for Open or OpenFat) in Go before 1.16.10 and 1.17.x before 1.17.3 Accesses a Memory Location After the End of a Buffer, aka an out-of-bounds slice situation.

Go before 1.16.10 and 1.17.x before 1.17.3 allows an archive/zip Reader.Open panic via a crafted ZIP archive containing an invalid name or an empty filename field.

In archive/zip in Go before 1.16.8 and 1.17.x before 1.17.1, a crafted archive header (falsely designating that many files are present) can cause a NewReader or OpenReader panic. NOTE: this issue exists because of an incomplete fix for CVE-2021-33196.

golang.org/x/text/language in golang.org/x/text before 0.3.7 can panic with an out-of-bounds read during BCP 47 language tag parsing. Index calculation is mishandled. If parsing untrusted user input, this can be used as a vector for a denial-of-service attack.

The TIFF decoder does not place a limit on the size of PackBits-compressed data. A maliciously-crafted image can exploit this to cause a small image (both in terms of pixel width/height and encoded size) to make the decoder decode large amounts of compressed data.

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.

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.

Within HostnameError.Error(), when constructing an error string, there is no limit to the number of hosts that will be printed out. Furthermore, the error string is constructed by repeated string concatenation, leading to quadratic runtime. Therefore, a certificate provided by a malicious actor can result in excessive resource consumption.

In archive/zip in Go before 1.15.13 and 1.16.x before 1.16.5, a crafted file count (in an archive's header) can cause a NewReader or OpenReader panic.

golang.org/x/net before v0.0.0-20210520170846-37e1c6afe023 allows attackers to cause a denial of service (infinite loop) via crafted ParseFragment input.

In Go before 1.15.13 and 1.16.x before 1.16.5, there can be a panic for a large exponent to the math/big.Rat SetString or UnmarshalText method.

An incorrectly placed cast from bytes to int allowed for server-side panic in the AES-GCM packet decoder for well-crafted inputs.

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.

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.

encoding/xml in Go before 1.15.9 and 1.16.x before 1.16.1 has an infinite loop if a custom TokenReader (for xml.NewTokenDecoder) returns EOF in the middle of an element. This can occur in the Decode, DecodeElement, or Skip method.

A nil pointer dereference in the golang.org/x/crypto/ssh component through v0.0.0-20201203163018-be400aefbc4c for Go allows remote attackers to cause a denial of service against SSH servers.

Go before 1.14.12 and 1.15.x before 1.15.4 allows Denial of Service.

In x/text in Go before v0.3.5, a "slice bounds out of range" panic occurs in language.ParseAcceptLanguage while processing a BCP 47 tag. (x/text/language is supposed to be able to parse an HTTP Accept-Language header.)

In x/text in Go 1.15.4, an "index out of range" panic occurs in language.ParseAcceptLanguage while parsing the -u- extension. (x/text/language is supposed to be able to parse an HTTP Accept-Language header.)

HTTP and MIME header parsing can allocate large amounts of memory, even when parsing small inputs, potentially leading to a denial of service. Certain unusual patterns of input data can cause the common function used to parse HTTP and MIME headers to allocate substantially more memory than required to hold the parsed headers. An attacker can exploit this behavior to cause an HTTP server to allocate large amounts of memory from a small request, potentially leading to memory exhaustion and a denial of service. With fix, header parsing now correctly allocates only the memory required to hold parsed headers.

Calling any of the Parse functions on Go source code which contains //line directives with very large line numbers can cause an infinite loop due to integer overflow.

The RSA and DSA public key parsers did not enforce size limits on key parameters. A crafted public key with an excessively large modulus or DSA parameter could cause several minutes of CPU consumption during signature verification. This could be triggered by unauthenticated clients during public key authentication. RSA moduli are now limited to 8192 bits, and DSA parameters are validated per FIPS 186-2.

Go before 1.13.15 and 14.x before 1.14.7 can have an infinite read loop in ReadUvarint and ReadVarint in encoding/binary via invalid inputs.

The html package (aka x/net/html) through 2018-09-17 in Go mishandles <math><template><mo><template>, leading to a "panic: runtime error" in parseCurrentToken in parse.go during an html.Parse call.

The html package (aka x/net/html) through 2018-09-25 in Go mishandles <math><template><mn><b></template>, leading to a "panic: runtime error" (index out of range) in (*insertionModeStack).pop in node.go, called from inHeadIM, during an html.Parse call.

The html package (aka x/net/html) through 2018-09-17 in Go mishandles <template><tBody><isindex/action=0>, leading to a "panic: runtime error" in inBodyIM in parse.go during an html.Parse call.

The html package (aka x/net/html) through 2018-09-25 in Go mishandles <svg><template><desc><t><svg></template>, leading to a "panic: runtime error" (index out of range) in (*nodeStack).pop in node.go, called from (*parser).clearActiveFormattingElements, during an html.Parse call.

QUIC connections do not set an upper bound on the amount of data buffered when reading post-handshake messages, allowing a malicious QUIC connection to cause unbounded memory growth. With fix, connections now consistently reject messages larger than 65KiB in size.