go1.20.12 (released 2023-12-05) includes security fixes to the go command,
and the net/http and path/filepath packages, as well as bug fixes to the
compiler and the go command. See the Go 1.20.12 milestone on our issue
tracker for details:

- https://github.com/golang/go/issues?q=milestone%3AGo1.20.12+label%3ACherryPickApproved
- full diff: golang/go@go1.20.11...go1.20.12

from the security mailing:

[security] Go 1.21.5 and Go 1.20.12 are released

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.

Signed-off-by: Sebastiaan van Stijn <[email protected]>