[security] Go 1.21.5 and Go 1.20.12 are released

[anno...@golang.org]

Hello gophers,

We have just released Go versions 1.21.5 and 1.20.12, minor point releases.

These minor releases include 3 security fixes following the security policy:

• net/http: limit chunked data overhead

  A malicious HTTP sender can use chunk extensions to cause a receiver reading from a request or response body to read many more bytes from the network than are in the body.

  A malicious HTTP client can further exploit this to cause a server to automatically read a large amount of data (up to about 1GiB) when a handler fails to read the entire body of a request.

  Chunk extensions are a little-used HTTP feature which permit including additional metadata in a request or response body sent using the chunked encoding. The net/http chunked encoding reader discards this metadata. A sender can exploit this by inserting a large metadata segment with each byte transferred. The chunk reader now produces an error if the ratio of real body to encoded bytes grows too small.

  Thanks to Bartek Nowotarski for reporting this issue.

  This is CVE-2023-39326 and Go issue https://go.dev/issue/64433.

• cmd/go: go get may unexpectedly fallback to insecure git

  Using go get to fetch a module with the ".git" suffix may unexpectedly fallback
  to the insecure "git://" protocol if the module is unavailable via the secure
  "https://" and "git+ssh://" protocols, even if GOINSECURE is not set for said
  module. This only affects users who are not using the module proxy and are
  fetching modules directly (i.e. GOPROXY=off).

  Thanks to David Leadbeater for reporting this issue.

  This is CVE-2023-45285 and Go issue https://go.dev/issue/63845.

• path/filepath: retain trailing \ when cleaning paths like \\?\c:\

  Go 1.20.11 and Go 1.21.4 inadvertently changed the definition of the volume name in Windows paths starting with \\?\, resulting in filepath.Clean(\\?\c:\) returning \\?\c: rather than \\?\c:\ (among other effects). The previous behavior has been restored.

  This is an update to CVE-2023-45283 and Go issue https://go.dev/issue/64028.

View the release notes for more information:
https://go.dev/doc/devel/release#go1.21.5

You can download binary and source distributions from the Go website:
https://go.dev/dl/

To compile from source using a Git clone, update to the release with
git checkout go1.21.5 and build as usual.

Thanks to everyone who contributed to the releases.

Cheers,
Carlos and Dmitri for the Go team