Issue #22198 has been updated by k0kubun (Takashi Kokubun). Backport changed from 3.3: REQUIRED, 3.4: DONE, 4.0: REQUIRED to 3.3: REQUIRED, 3.4: DONE, 4.0: DONE ruby_4_0 commit:b7193103f5cf003e5880531133694977e64e8d04. ---------------------------------------- Bug #22198: win32: heap overflow in Kernel#system https://bugs.ruby-lang.org/issues/22198#change-119007 * Author: mame (Yusuke Endoh) * Status: Closed * Assignee: windows * ruby -v: ruby 4.0.6 (2026-07-14 revision 03b6d3f889) +PRISM [x64-mingw-ucrt] * Backport: 3.3: REQUIRED, 3.4: DONE, 4.0: DONE ---------------------------------------- `system('foo.exe %A')` looks past `%A` for a closing `%`, reading past the end of the string. It does not reproduce normally, but with page heap enabled it faults: ``` PS C:\> gflags /p /enable ruby.exe /full PS C:\> ruby -e "system('x' * 1024 + '.exe %A')" -e:1: [BUG] Segmentation fault ruby 4.0.6 (2026-07-14 revision 03b6d3f889) +PRISM [x64-mingw-ucrt] -- Control frame information ----------------------------------------------- c:0003 p:---- s:0011 e:000010 l:y b:0001 CFUNC :system c:0002 p:0013 s:0006 e:000005 l:n b:---- EVAL -e:1 [FINISH] c:0001 p:0000 s:0003 E:001620 l:y b:---- DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- -e:1:in '<main>' -e:1:in 'system' -- Threading information --------------------------------------------------- Total ractor count: 1 Ruby thread count for this ractor: 1 -- C level backtrace information ------------------------------------------- C:\WINDOWS\SYSTEM32\ntdll.dll(NtWaitForSingleObject+0x14) [0x00007ffbd55000e4] C:\WINDOWS\System32\KERNELBASE.dll(WaitForSingleObjectEx+0xaf) [0x00007ffbd274c11f] C:\Users\YusukeEndoh\scoop\apps\ruby\current\bin\x64-ucrt-ruby400.dll(rb_vm_bugreport+0x237) [0x00007ffb37262227] C:\Users\YusukeEndoh\scoop\apps\ruby\current\bin\x64-ucrt-ruby400.dll(rb_bug_for_fatal_signal+0x9b) [0x00007ffb37000beb] C:\Users\YusukeEndoh\scoop\apps\ruby\current\bin\x64-ucrt-ruby400.dll(rb_shape_free_all+0xfb5) [0x00007ffb37191985] C:\WINDOWS\System32\ucrtbase.dll(seh_filter_exe+0x84) [0x00007ffbd2fff2e4] [0x00007ff765e81080] C:\WINDOWS\SYSTEM32\ntdll.dll(_chkstk+0x9f) [0x00007ffbd550479f] *snip* ``` PR: https://github.com/ruby/ruby/pull/17929 -- https://bugs.ruby-lang.org/