CVE-2020-13354: 
GitLab vulnerability analysis and mitigation

CVE-2020-13354 is a potential Denial of Service (DoS) vulnerability discovered in GitLab Community Edition (CE) and Enterprise Edition (EE) versions starting from 12.6. The vulnerability was identified in the container registry name check functionality, which could cause an exponential number of backtracks for certain user-supplied values, resulting in high CPU usage (GitLab Security Release).

The vulnerability exists in the container registry name validation mechanism where the container_repository_name_regex contains a pattern susceptible to catastrophic backtracking. When processing certain specially crafted repository names (up to 255 characters), the regex pattern could trigger excessive CPU consumption due to the backtracking behavior (GitLab Issue).

The exploitation of this vulnerability could lead to a Denial of Service condition through high CPU usage when processing certain container registry names. This could potentially affect the availability of the GitLab instance by consuming excessive server resources (GitLab Security Release).

The vulnerability can be triggered by submitting specially crafted container repository names that cause the regex pattern to enter into a catastrophic backtracking state. The issue was reported through GitLab's HackerOne bug bounty program by researcher @anyday (GitLab Security Release).

The vulnerability has been fixed in GitLab versions 13.5.2, 13.4.5, and 13.3.9. GitLab strongly recommends that all installations running affected versions be upgraded to the latest version immediately (GitLab Security Release).