Issue #21344 has been updated by nagachika (Tomoyuki Chikanaga). Backport changed from 3.2: REQUIRED, 3.3: REQUIRED, 3.4: DONTNEED to 3.2: REQUIRED, 3.3: DONE, 3.4: DONTNEED ruby_3_3 commit:1f226f1efeeae3a5091c60e2f51e027d0598f394 merged revision(s) commit:b959263b58e26ef630c085f9f7ddc04373a998c7. ---------------------------------------- Bug #21344: Segment Fault Caused by no Backported Patches https://bugs.ruby-lang.org/issues/21344#change-113329 * Author: tianstcht (Haotian Cheng) * Status: Closed * ruby -v: 3.2.3 (2024-01-18 revision 52bb2ac0a6) [x86_64-linux-gnu] * Backport: 3.2: REQUIRED, 3.3: DONE, 3.4: DONTNEED ---------------------------------------- In my local machine(3.2.3 (2024-01-18 revision 52bb2ac0a6) [x86_64-linux-gnu]), which is the default version in ubuntu2404, a segmentation fault can be stably triggered by the poc including malicious xml data. The poc here: ```ruby require "rexml/document" puts REXML::VERSION def poc1(size) input = <<EOF <mydoc> <tt>#{'&' + '1'*size + '#x2F3F' + ' '}</tt> </mydoc> EOF parser = REXML::Document.new input end poc1(8_999_999) ``` The issue has been fixed in this commit: https://github.com/ruby/ruby/commit/b959263b58e26ef630c085f9f7ddc04373a998c7 But the fix haven't been backported to Ruby 3.2 and 3.3. Based on the developer's response, I think the backporting may be needed so the issue built. -- https://bugs.ruby-lang.org/