This patch fixes a security issue where snmp_pdu_parse() function 
could leave incompletely parsed varBind variables in the list of  
variables. A remote, unauthenticated attacker could exploit this 
flaw to cause a crash or, potentially, execute arbitrary code.
The vulnerability is fixed in the upsream and below is the link 
to the upstream bug.
https://sourceforge.net/p/net-snmp/bugs/2615/ 

--- net-snmp-5.4.1/snmplib/snmp_api.c	2016-09-20 04:29:08.940393100 -0700
+++ copy_net-snmp-5.4.1/snmplib/snmp_api.c	2016-09-20 04:50:11.450793400 -0700
@@ -4273,7 +4273,7 @@
     int             badtype = 0;
     size_t          len;
     size_t          four;
-    netsnmp_variable_list *vp = NULL;
+    netsnmp_variable_list *vp = NULL, *vplast = NULL;
     oid             objid[MAX_OID_LEN];
 
     /*
@@ -4408,38 +4408,24 @@
                               (ASN_SEQUENCE | ASN_CONSTRUCTOR),
                               "varbinds");
     if (data == NULL)
-        return -1;
+	goto fail;
 
     /*
      * get each varBind sequence 
      */
     while ((int) *length > 0) {
-        netsnmp_variable_list *vptemp;
-        vptemp = (netsnmp_variable_list *) malloc(sizeof(*vptemp));
-        if (0 == vptemp) {
-            return -1;
-        }
-        if (0 == vp) {
-            pdu->variables = vptemp;
-        } else {
-            vp->next_variable = vptemp;
-        }
-        vp = vptemp;
-
-        vp->next_variable = NULL;
-        vp->val.string = NULL;
+	 vp = SNMP_MALLOC_TYPEDEF(netsnmp_variable_list);
+        if (NULL == vp)
+            goto fail;
         vp->name_length = MAX_OID_LEN;
-        vp->name = 0;
-        vp->index = 0;
-        vp->data = 0;
-        vp->dataFreeHook = 0;
+	 vp->type = 0;
         DEBUGDUMPSECTION("recv", "VarBind");
         data = snmp_parse_var_op(data, objid, &vp->name_length, &vp->type,
                                  &vp->val_len, &var_val, length);
         if (data == NULL)
-            return -1;
+		goto fail;
         if (snmp_set_var_objid(vp, objid, vp->name_length))
-            return -1;
+		goto fail;
 
         len = MAX_PACKET_LENGTH;
         DEBUGDUMPHEADER("recv", "Value");
@@ -4504,7 +4490,7 @@
                 vp->val.string = (u_char *) malloc(vp->val_len);
             }
             if (vp->val.string == NULL) {
-                return -1;
+		goto fail;
             }
             asn_parse_string(var_val, &len, &vp->type, vp->val.string,
                              &vp->val_len);
@@ -4515,7 +4501,7 @@
             vp->val_len *= sizeof(oid);
             vp->val.objid = (oid *) malloc(vp->val_len);
             if (vp->val.objid == NULL) {
-                return -1;
+		goto fail;
             }
             memmove(vp->val.objid, objid, vp->val_len);
             break;
@@ -4527,19 +4513,32 @@
         case ASN_BIT_STR:
             vp->val.bitstring = (u_char *) malloc(vp->val_len);
             if (vp->val.bitstring == NULL) {
-                return -1;
+		goto fail;
             }
             asn_parse_bitstring(var_val, &len, &vp->type,
                                 vp->val.bitstring, &vp->val_len);
             break;
         default:
             snmp_log(LOG_ERR, "bad type returned (%x)\n", vp->type);
-            badtype = -1;
+	    goto fail;
             break;
         }
         DEBUGINDENTADD(-4);
+	 if (NULL == vplast) {
+            pdu->variables = vp;
+        } else {
+            vplast->next_variable = vp;
+        }
+        vplast = vp;
+        vp = NULL;
     }
-    return badtype;
+    return 0;
+    fail:
+      DEBUGMSGTL(("recv", "error while parsing VarBindList\n"));
+      /** if we were parsing a var, remove it from the pdu and free it */
+      if (vp)
+        snmp_free_var(vp);
+      return -1;
 }
 
 /*