gitoxide is a pure Rust implementation of Git. `gix-transport` does not check the username part of a URL for text that the external `ssh` program would interpret as an option. A specially crafted clone URL can smuggle options to SSH. The possibilities are syntactically limited, but if a malicious clone URL is used by an application whose current working directory contains a malicious file, arbitrary code execution occurs. This is related to the patched vulnerability GHSA-rrjw-j4m2-mf34, but appears less severe due to a greater attack complexity. This issue has been patched in versions 0.35.0, 0.42.0 and 0.62.0.

Affected: crates.io: gix-transport, crates.io: gix, crates.io: gitoxide

### Summary

`gix-transport` does not check the username part of a URL for text that the external `ssh` program would interpret as an option. A specially crafted clone URL can smuggle options to SSH. The possibilities are syntactically limited, but if a malicious clone URL is used by an application whose current working directory contains a malicious file, arbitrary code execution occurs.

### Details

This is related to the patched vulnerability https://github.com/advisories/GHSA-rrjw-j4m2-mf34, but appears less severe due to a greater attack complexity. Since https://github.com/Byron/gitoxide/pull/1032, `gix-transport` checks the host and path portions of a URL for text that has a `-` in a position that will cause `ssh` to interpret part of all of the URL as an option argument. But it does not check the non-mandatory username portion of the URL.

As in Git, when an address is a URL of the form `ssh://username@hostname/path`, or when it takes the special form `username@hostname:dirs/repo`, this is treated as an SSH URL. `gix-transport` will replace some characters in `username` with their `%`-based URL encodings, but otherwise passes `username@hostname` as an argument to the external `ssh` command. This happens even if `username` begins with a hyphen. In that case, `ssh` treats that argument as an option argument, and attempts to interpret and honor it as a sequence of one or more options possibly followed by an operand for the last option.

This is harder to exploit than G…

Affected: crates.io: gix-transport

### Summary

`gix-transport` does not check the username part of a URL for text that the external `ssh` program would interpret as an option. A specially crafted clone URL can smuggle options to SSH. The possibilities are syntactically limited, but if a malicious clone URL is used by an application whose current working directory contains a malicious file, arbitrary code execution occurs.

The first `gix` crate with the fix [is version 0.62.0](https://crates.io/crates/gix/0.62.0), and the first fixed `gix` CLI is [version 0.35](https://github.com/Byron/gitoxide/releases/tag/v0.35.0). `gix-transport` [at version v0.42](https://crates.io/crates/gix-transport/0.42.0) is the lowest-level plumbing crate with the fix.

### Details

This is related to the patched vulnerability [RUSTSEC-2023-0064](https://rustsec.org/advisories/RUSTSEC-2023-0064.html), but appears less severe due to a greater attack complexity. Since <https://github.com/Byron/gitoxide/pull/1032>, `gix-transport` checks the host and path portions of a URL for text that has a `-` in a position that will cause `ssh` to interpret part of all of the URL as an option argument. But it does not check the non-mandatory username portion of the URL.

As in Git, when an address is a URL of the form `ssh://username@hostname/path`, or when it takes the special form `username@hostname:dirs/repo`, this is treated as an SSH URL. `gix-transport` will replace some characters in `username` with their `%`-based URL encodings, but otherw…