RUSTSEC-2020-0068

Unexpected panic in multihash from_slice parsing code

Reported

November 8, 2020

Issued

November 9, 2020 (last modified: October 19, 2021)

Package

multihash (crates.io)

Type

Vulnerability

Categories

denial-of-service

Keywords

#parsing #panic #untrusted-data

Aliases

CVE-2020-35909

Details

https://github.com/multiformats/rust-multihash/pull/72

CVSS Score

7.5 HIGH

CVSS Details

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Patched

>=0.11.3

Affected Functions

Version

multihash::digests::MultihashGeneric::from_bytes

<0.11.3

multihash::digests::MultihashRefGeneric::from_slice

<0.11.3

Description

In versions prior 0.11.3 it's possible to make from_slice panic by feeding it certain malformed input. It's never documented that from_slice (and from_bytes which wraps it) can panic, and its' return type (Result<Self, DecodeError>) suggests otherwise.

In practice, from_slice/from_bytes is frequently used in networking code (for example in rust-libp2p) and is being called with unsanitized data from untrusted sources. This can allow attackers to cause DoS by causing an unexpected panic in the network client's code.