Matrix's largest server, matrix.org, and its infrastructure were subject to a hacker attack that exposed security problems. User matrixnotorg created tickets on Github describing problems existing in the matrix.org infrastructure and their possible solution.
The infrastructure was accessed through a hole in an outdated version of Jenkins, the continuous deployment system that matrix.org uses.
According to matrix.org, the repositories and their Docker Hub are not compromised.
Source: linux.org.ru