CVE-2024-48924 – MessagePack allows untrusted data to lead to DoS attack due to hash collisions and stack overflow

https://notcve.org/view.php?id=CVE-2024-48924

### Impact When this library is used to deserialize messagepack data from an untrusted source, there is a risk of a denial of service attack by an attacker that sends data contrived to produce hash collisions, leading to large CPU consumption disproportionate to the size of the data being deserialized. This is similar to [a prior advisory](https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-7q36-4xx7-xcxf), which provided an inadequate fix for the hash collision part of the vulnerability. ### Patches The following steps are required to mitigate this risk. 1. Upgrade to a version of the library where a fix is available. 1. Review the steps in [this previous advisory](https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-7q36-4xx7-xcxf) to ensure you have your application configured for untrusted data. ### Workarounds If upgrading MessagePack to a patched version is not an option for you, you may apply a manual workaround as follows: 1. Declare a class that derives from `MessagePackSecurity`. 2. Override the `GetHashCollisionResistantEqualityComparer<T>` method to provide a collision-resistant hash function of your own and avoid calling `base.GetHashCollisionResistantEqualityComparer<T>()`. 3. • https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/8e599af0798b45008f8b293a7f233e4878f11ed5 https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/f8d40b3ad0be01c6e56cb51ecea81f59d98c192d https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-4qm4-8hg2-g2xm • CWE-328: Use of Weak Hash •