An attacker who already had access to the environment could so append values to parameters passed through programs.
| Package | app-shells/mksh on all architectures | 
|---|---|
| Affected versions | < 50c | 
| Unaffected versions | >= 50c | 
MirBSD Korn Shell is an actively developed free implementation of the Korn Shell programming language and a successor to the Public Domain Korn Shell.
Improper sanitation of environment import allows for appending of values to passed parameters.
An attacker who already had access to the environment could so append values to parameters passed through programs (including sudo(8) or setuid) to shell scripts, including indirectly, after those programs intended to sanitise the environment, e.g. invalidating the last $PATH component.
There is no known workaround at this time.
All mksh users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=app-shells/mksh-50c"
      Release date
      
      November 02, 2015
    
      Latest revision
      
      November 02, 2015: 2
    
      Severity
      
      normal
    
      Exploitable
      
      local
    
Bugzilla entries