Implementation bug in the go client leads to steady increase of difficulty independent of hashing power.

Affected configurations: All Go client versions v1.0.x, v1.1.x, release and develop branches. The bug was introduced in a recent update and release through commit https://github.com/ethereum/go-ethereum/commit/7324176f702a77fc331bf16a968d2eb4bccce021 which went into the affected client versions. All miners running earlier mentioned versions are affected and are advised to update as soon as possible.

Likelihood: High

Severity: Medium

Impact: Increase in block time will lead to an exponential increase in difficulty

Details: A bug in the go client leads to steady increase in difficulty in the following block, as timestamp in new block = timestamp + 1 of old block, regardless of the actual time, when mining. This leads to an increase in the difficulty independently of the hashing power

Effects on expected chain reorganisation depth: None

Proposed temporary workaround: None

Remedial action taken by Ethereum: Provision of hotfixes as below:

If using the PPA: sudo apt-get update then sudo apt-get upgrade

If using brew: brew update then brew reinstall ethereum

If using a windows binary: download the updated binary from the release page