[asterisk-security] AST-2021-004: An unsuspecting user could crash Asterisk with multiple hold/unhold requests

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2021-004

         Product        Asterisk                                              
         Summary        An unsuspecting user could crash Asterisk with        
                        multiple hold/unhold requests                         
    Nature of Advisory  Denial of Service                                     
      Susceptibility    Remote authenticated sessions                         
         Severity       Moderate                                              
      Exploits Known    No                                                    
       Reported On      December 9, 2020                                      
       Reported By      Edvin Vidmar                                          
        Posted On       
     Last Updated On    February 11, 2021                                     
     Advisory Contact   gjoseph AT sangoma DOT com                            
         CVE Name       CVE-2021-26714                                        

      Description     Due to a signedness comparison mismatch, an             
                      authenticated WebRTC client could cause a stack         
                      overflow and Asterisk crash by sending multiple         
                      hold/unhold requests in quick succession.               
    Modules Affected  res_rtp_asterisk.c                                      

      Resolution    The packet size comparison terms have been corrected.     

                               Affected Versions
                Product               Release Series  
          Asterisk Open Source             16.x       16.16.0                 
          Asterisk Open Source             17.x       17.9.1                  
          Asterisk Open Source             18.x       18.2.0                  
           Certified Asterisk              16.x       16.8-cert5              

                                  Corrected In
                 Product                              Release                 
           Asterisk Open Source               16.16.1, 17.9.2, 18.2.1         
            Certified Asterisk                       16.8-cert6               

                                     Patches                         
                               Patch URL                              Revision  
   https:/downloads.asterisk.org/pub/security/AST-2021-004-16.diff   Asterisk   
                                                                     16         
   https:/downloads.asterisk.org/pub/security/AST-2021-004-17.diff   Asterisk   
                                                                     17         
   https:/downloads.asterisk.org/pub/security/AST-2021-004-18.diff   Asterisk   
                                                                     18         
   https:/downloads.asterisk.org/pub/security/AST-2021-004-16.8.diff Certified  
                                                                     Asterisk   
                                                                     16.8-cert6 

     Links   https://issues.asterisk.org/jira/browse/ASTERISK-29205           
                                                                              
             https://downloads.asterisk.org/pub/security/AST-2021-004.html    

    Asterisk Project Security Advisories are posted at                        
    http://www.asterisk.org/security                                          
                                                                              
    This document may be superseded by later versions; if so, the latest      
    version will be posted at                                                 
    https://downloads.digium.com/pub/security/AST-2021-004.pdf and            
    https://downloads.digium.com/pub/security/AST-2021-004.html               

                                Revision History
          Date                  Editor                 Revisions Made         
    February 4, 2021   George Joseph             Initial revision             
    February 9, 2021   George Joseph             Added CVE                    

               Asterisk Project Security Advisory - AST-2021-004
               Copyright © 2021 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.