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High 7.5
HTTP/2 server crash due to HPACK encoder race in net/http
HTTP/2 servers could end up crashing due to inadvertently modifying its HPACK encoder concurrently. This happens because the server modifies the HPACK encoder from two goroutines without synchronization: one uses the encoder to encode a HEADERS frame as part …
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High 7.5
HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the …
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High 7.5
HTTP/2 transport accepts malformed framing-related headers in net/http
Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such header…
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Critical 9.1
Double flow control refund on HTTP/2 server streams in net/http
The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client…
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High 7.5
Excessive CPU consumption from repeated initial window changes in net/http
A malicious HTTP/2 peer can cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values.
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High 7.5
Memory limit bypass when parsing MIME headers in net/textproto, mime/multipart
Parsing a multipart form can bypass memory limits and read an arbitrarily long line into memory when the remaining limit at the start of a part is less than 400 bytes.
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High 7.5
Reject malformed ECH outer extension references in crypto/tls
Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and …
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High 7.5
HTTP/1 client connection desynchronization after CONNECT rejection in net/http
When http.Transport sends an HTTP/1 CONNECT request with a non-empty Request.Body, it writes the body directly to the connection without framing after the request headers. If the server rejects the CONNECT request with a non-2xx keep-alive response, Transport…
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High 7.5
HTTP/2 server memory exhaustion due to Trailer headers in net/http
When "Trailer" headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicio…
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Medium 6.1
Reset context tracking on consecutive template expressions in html/template
When a JavaScript template literal contains consecutive expressions, the context tracking state was not properly reset upon entering a new expression. We now ensure that template-literal expression entries correctly reset context variables so all subsequent r…
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Medium 6.1
Recognize yield as regexp preceder keyword in html/template
A trusted template author may have previously written a valid template wherein the use of the 'yield' keyword would not be correctly escaped. We now ensure that valid keyword uses are escaped and non-keyword uses are not escaped.
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Medium 5.3
Invoking Encrypted Client Hello privacy leak in crypto/tls
Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.
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Medium 5.3
Arbitrary inputs are included in errors without any escaping in net/textproto
When returning errors, functions in the net/textproto package would include its input as part of the error. This might allow an attacker to inject misleading content to errors that are printed or logged.
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Medium 6.5CVE-2026-27145 Public exploit
Inefficient candidate hostname parsing in crypto/x509
(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification c…
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Medium 6.1
Escaper bypass leads to XSS in html/template
If a trusted template author were to write a <script> tag containing an empty 'type' attribute or a 'type' attribute with an ASCII whitespace, the execution of the template would incorrectly escape any data passed into the <script> block.
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Medium 6.1
Bypass of meta content URL escaping causes XSS in html/template
CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a <meta> tag's <content> attribute. If the URL content were to insert ASCII whitespaces around the '=' rune inside of the <content> attribute, the escaper would fail to si…
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High 7.5
Malicious module proxy can bypass checksum database in cmd/go
A malicious module proxy can exploit a flaw in the go command's validation of module checksums to bypass checksum database validation. This vulnerability affects any user using an untrusted module proxy (GOMODPROXY) or checksum database (GOSUMDB). A malicious…
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Medium 5.9
Invoking "go tool pack" does not sanitize output paths in cmd/go
The "go tool pack" subcommand (usually used only by the compiler as an internal tool with known-good inputs) does not sanitize output filenames. Extracting a malicious archive file with the "pack" subcommand can write files to arbitrary locations on the files…
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Medium 5.3
Invoking "go bug" follows symlinks in predictable temporary filenames in cmd/go
The "go bug" command writes to two files with predictable names in the system temporary directory (for example, "/tmp"). An attacker with access to the temporary directory can create a symlink in one of these names, causing "go bug" to overwrite the target of…
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High 7.5
Panic in Dial and LookupPort when handling NUL byte on Windows in net
The Dial and LookupPort functions panic on Windows when provided with an input containing a NUL (0).
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High 7.5
Infinite loop in HTTP/2 transport when given bad SETTINGS_MAX_FRAME_SIZE in net/http/internal/http2 in golang.org/x/net
When processing HTTP/2 SETTINGS frames, transport will enter an infinite loop of writing CONTINUATION frames if it receives a SETTINGS_MAX_FRAME_SIZE with a value of 0.
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High 7.5
Inefficient policy validation in crypto/x509
Validating certificate chains which use policies is unexpectedly inefficient when certificates in the chain contain a very large number of policy mappings, possibly causing denial of service. This only affects validation of otherwise trusted certificate chain…
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High 7.5
Unexpected work during chain building in crypto/x509
During chain building, the amount of work that is done is not correctly limited when a large number of intermediate certificates are passed in VerifyOptions.Intermediates, which can lead to a denial of service. This affects both direct users of crypto/x509 an…
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High 7.5
Unauthenticated TLS 1.3 KeyUpdate record can cause persistent connection retention and DoS in crypto/tls
If one side of the TLS connection sends multiple key update messages post-handshake in a single record, the connection can deadlock, causing uncontrolled consumption of resources. This can lead to a denial of service. This only affects TLS 1.3.
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High 8.8
Code execution vulnerability in SWIG code generation in cmd/go
SWIG file names containing 'cgo' and well-crafted payloads could lead to code smuggling and arbitrary code execution at build time due to trust layer bypass.
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Medium 6.1
JsBraceDepth Context Tracking Bugs (XSS) in html/template
Context was not properly tracked across template branches for JS template literals, leading to possibly incorrect escaping of content when branches were used. Additionally template actions within JS template literals did not properly track the brace depth, le…
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Low 2.5
FileInfo can escape from a Root in os
On Unix platforms, when listing the contents of a directory using File.ReadDir or File.Readdir the returned FileInfo could reference a file outside of the Root in which the File was opened. The impact of this escape is limited to reading metadata provided by …
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Medium 6.1
URLs in meta content attribute actions are not escaped in html/template
Actions which insert URLs into the content attribute of HTML meta tags are not escaped. This can allow XSS if the meta tag also has an http-equiv attribute with the value "refresh". A new GODEBUG setting has been added, htmlmetacontenturlescape, which can be …
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High 7.5
Incorrect parsing of IPv6 host literals in net/url
url.Parse insufficiently validated the host/authority component and accepted some invalid URLs.
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Critical 9.1
Unexpected session resumption in crypto/tls
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 ca…
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High 8.6
Potential code smuggling via doc comments in cmd/cgo
A discrepancy between how Go and C/C++ comments were parsed allowed for code smuggling into the resulting cgo binary.
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High 7.5
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-encode…
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High 7.8
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 com…
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Medium 5.3
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 c…
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High 7.0
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 exter…
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High 7.5
Excessive resource consumption when printing error string for host certificate validation in crypto/x509
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 certi…
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Medium 5.3
Malformed constraint may cause denial of service in golang.org/x/crypto/ssh/agent
SSH Agent servers do not validate the size of messages when processing new identity requests, which may cause the program to panic if the message is malformed due to an out of bounds read.
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Medium 5.3
Unbounded memory consumption in golang.org/x/crypto/ssh
SSH servers parsing GSSAPI authentication requests do not validate the number of mechanisms specified in the request, allowing an attacker to cause unbounded memory consumption.
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High 7.0
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…