CVE-2021-32742

Vapor is a web framework for Swift. In versions 4.47.1 and prior, bug in the Data.init(base32Encoded:) function opens up the potential for exposing server memory and/or crashing the server (Denial of Service) for applications where untrusted data can end up in said function. Vapor does not currently use this function itself so this only impact applications that use the impacted function directly or through other dependencies. The vulnerability is patched in version 4.47.2. As a workaround, one may use an alternative to Vapors built-in Data.init(base32Encoded:).

Weakness

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Software

Potential Mitigations

• Make fields transient to protect them from deserialization.
• An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/586.html

References

• https://github.com/vapor/vapor/releases/tag/4.47.2
• https://github.com/vapor/vapor/security/advisories/GHSA-pqwh-c2f3-vxmq
• https://github.com/vapor/vapor/releases/tag/4.47.2
• https://github.com/vapor/vapor/security/advisories/GHSA-pqwh-c2f3-vxmq