An issue has been discovered in GitLab CE/EE affecting all versions from 7.0 before 18.11.13, 19.0 before 19.0.10, 19.1 before 19.1.9, 19.2 before 19.2.9, 19.3 before 19.3.6, 19.4 before 19.4.3, and 19.5 before 19.5.1 that, under certain conditions, could have allowed an unauthenticated user to execute arbitrary code on the GitLab server due to integer overflow when compiling a specially crafted regular expression. Note: The vulnerable code resides in regcomp.c in Ruby’s bundled Onigmo regular expression engine, rather than GitLab’s own application source. GitLab ships Ruby with its packages and applies a patch to that bundled runtime. The upstream fix is Ruby commit 493d26dc.