CVE-2022-36113 is a medium-severity path traversal vulnerability affecting Cargo, the package manager for the Rust programming language. Cargo downloads Rust packages and extracts their source code into the ~/.cargo directory. To mark successful extraction, Cargo writes the string "ok" into a file named .cargo-ok at the root of the extracted package. The vulnerability arises because Cargo does not properly restrict symbolic links within packages. Specifically, if a package contains a .cargo-ok symbolic link pointing to an arbitrary file elsewhere on the filesystem, Cargo will follow this symlink and overwrite the first two bytes of the target file with "ok" during extraction. This allows an attacker to corrupt arbitrary files on the victim's machine where Cargo is run. The vulnerability affects all Cargo versions prior to 0.65.0 and version 0.66.0. Although the impact is limited to partial file corruption (overwriting only two bytes), this can cause unpredictable behavior or data corruption in critical files. The flaw is a subset of the broader risk posed by Cargo’s design, which inherently allows arbitrary code execution at build time via build scripts and procedural macros. Thus, while this vulnerability enables a stealthier and harder-to-detect attack vector, it does not expand the fundamental attack surface beyond what malicious build scripts already permit. The Rust 1.64 release includes a fix for this issue, but no backported patches are provided for earlier Rust versions. Users building their own toolchains can apply patches from the wg-security-response repository. The official crates.io registry has server-side checks that reject packages exploiting this vulnerability, and no known exploits have been observed in the wild. However, users of alternate registries or untrusted packages remain at risk. Overall, the vulnerability is a path traversal flaw (CWE-22) that allows limited arbitrary file corruption during package extraction, compounding the inherent risks of Cargo’s build-time code execution model.

For European organizations, the impact of CVE-2022-36113 is primarily related to the integrity of development environments and build pipelines that use Cargo. Since Cargo is widely used in Rust development, organizations relying on Rust for critical applications or infrastructure could face subtle file corruption leading to build failures, corrupted binaries, or compromised software integrity. Although the vulnerability does not directly enable remote code execution beyond what build scripts already allow, it can be used to tamper with files in a stealthy manner, complicating forensic analysis and incident response. This could undermine trust in software supply chains, especially in sectors with stringent software integrity requirements such as finance, telecommunications, and critical infrastructure. The lack of known exploits in the wild and the presence of server-side checks on crates.io reduce immediate risk, but organizations using private or alternate registries may be more exposed. Additionally, since Cargo’s design inherently permits arbitrary code execution at build time, this vulnerability adds a subtle attack vector that could be leveraged by sophisticated threat actors targeting European software development environments. The potential impact includes disruption of software builds, introduction of hard-to-detect corruption in source or configuration files, and erosion of supply chain security assurances.

1. Upgrade Cargo to version 0.65.0 or later, or Rust 1.64 or later, where the vulnerability is fixed. If using custom toolchains, apply the patches available in the wg-security-response repository. 2. Restrict usage of alternate package registries and only include dependencies from trusted sources. Implement strict vetting and code review processes for third-party Rust packages, especially those from non-official registries. 3. Employ reproducible builds and integrity verification techniques such as checksums or signatures on dependencies to detect tampering or corruption caused by this vulnerability. 4. Monitor build environments for unexpected file modifications, particularly in ~/.cargo directories, using file integrity monitoring tools. 5. Isolate build environments using containerization or sandboxing to limit the impact of any file corruption or malicious build scripts. 6. Educate development teams about the inherent risks of build-time code execution in Cargo and enforce policies to minimize inclusion of untrusted dependencies. 7. For organizations running continuous integration pipelines, implement automated scanning of dependencies for known vulnerabilities and suspicious package contents, including symbolic links that could lead to path traversal. 8. Maintain up-to-date backups of critical build environment files to enable recovery from potential corruption.